/*
 * International Chemical Identifier (InChI)
 * Version 1
 * Software version 1.07
 * April 30, 2024
 *
 * MIT License
 *
 * Copyright (c) 2024 IUPAC and InChI Trust
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
*
* The InChI library and programs are free software developed under the
 * auspices of the International Union of Pure and Applied Chemistry (IUPAC).
 * Originally developed at NIST.
 * Modifications and additions by IUPAC and the InChI Trust.
 * Some portions of code were developed/changed by external contributors
 * (either contractor or volunteer) which are listed in the file
 * 'External-contributors' included in this distribution.
 *
 * info@inchi-trust.org
 *
*/

#include <stdlib.h>
#include <string.h>

/* */
/*#define CHECK_WIN32_VC_HEAP*/

#include "mode.h"

#if ( READ_INCHI_STRING == 1 )

#include "ichister.h"
#include "ichirvrs.h"

#include "bcf_s.h"

/****************************************************************************/
void CopyAt2St( inp_ATOM *at, inp_ATOM_STEREO * st, int num_atoms )
{
    int i;
    for (i = 0; i < num_atoms; i++)
    {
        if (at[i].p_parity)
        {
            memcpy(st[i].p_orig_at_num, at[i].p_orig_at_num, sizeof(st[0].p_orig_at_num));
            st[i].p_parity = at[i].p_parity;
        }
        if (at[i].sb_parity[0])
        {
            memcpy(st[i].sb_ord, at[i].sb_ord, sizeof(st[0].sb_ord));
            memcpy(st[i].sb_parity, at[i].sb_parity, sizeof(st[0].sb_parity));
            memcpy(st[i].sn_ord, at[i].sn_ord, sizeof(st[0].sn_ord));
            memcpy(st[i].sn_orig_at_num, at[i].sn_orig_at_num, sizeof(st[0].sn_orig_at_num));
        }
    }
}


/****************************************************************************/
void CopySt2At( inp_ATOM *at, inp_ATOM_STEREO * st, int num_atoms )
{
    int i;
    if (!st)
    {
        return;
    }

    for (i = 0; i < num_atoms; i++)
    {
        if (st[i].p_parity)
        {
            memcpy(at[i].p_orig_at_num, st[i].p_orig_at_num, sizeof(at[0].p_orig_at_num));
            at[i].p_parity = st[i].p_parity;
        }
        if (st[i].sb_parity[0])
        {
            memcpy(at[i].sb_ord, st[i].sb_ord, sizeof(st[0].sb_ord));
            memcpy(at[i].sb_parity, st[i].sb_parity, sizeof(at[0].sb_parity));
            memcpy(at[i].sn_ord, st[i].sn_ord, sizeof(at[0].sn_ord));
            memcpy(at[i].sn_orig_at_num, st[i].sn_orig_at_num, sizeof(at[0].sn_orig_at_num));
        }
    }
}


/****************************************************************************/
int RestoreAtomConnectionsSetStereo( StrFromINChI *pStruct,
                                     int iComponent,
                                     int iAtNoOffset,
                                     INChI *pInChI,
                                     INChI *pInChIMobH )
{
    inp_ATOM_STEREO *st = NULL;
    int           num_atoms, i, jv, jn, n_vertex, n_neigh, num_H, parity;
    int           nNumDeletedH = 0, iDeletedH = 0, idelH1, idelH2, ret = 0, len;
    int           num_stereo_bonds2, num_stereo_centers2; /* djb-rwth: removing redundant variables */
    INChI_Stereo *pStereo = NULL, *pStereo2 = NULL;
    AT_NUMB       nCumulene[MAX_CUMULENE_LEN + 2];
    inp_ATOM* at = NULL;  /* copied from below 2024-09-01 DT */

    num_atoms = pInChI->nNumberOfAtoms;
    if (num_atoms <= 0)
    {
        return 0;
    }

    INCHI_HEAPCHK

        /* atoms */
    at = (inp_ATOM*)inchi_calloc(num_atoms, sizeof(pStruct->at[0]));
    if (!at)
    {
        ret = RI_ERR_ALLOC;
        goto exit_function;
    }
    pStruct->at = at;
    pStruct->num_atoms = num_atoms;

    /* charge */
    pStruct->charge = pInChI->nTotalCharge;

    /* elements, terminal atoms H */
    for (i = 0; i < num_atoms; i++)
    {
        at[i].el_number = pInChI->nAtom[i];
        if (-1 == get_element_chemical_symbol( UCINT pInChI->nAtom[i], at[i].elname ))
        {
            ret = RI_ERR_PROGR;
            goto exit_function;
        }
        at[i].orig_at_number = iAtNoOffset + i + 1;
        at[i].orig_compt_at_numb = i + 1;
        at[i].component = iComponent + 1;
        num_H = pInChI->nNum_H[i];
        /* --- pInChI->nNum_H_fixed[i] was added to pInChI->nNum_H[i] ---
        if ( pInChI->nNum_H_fixed ) {
            num_H += pInChI->nNum_H_fixed[i];
        }
        */
#if 0
        ( FIX_GAF_ISSUES == 1 )
            if (num_H < 0)
            {
                ret = RI_ERR_PROGR;
                goto exit_function;
            }
#endif
        at[i].num_H = num_H;
    }

    INCHI_HEAPCHK

    /* connections */
    for (i = 1, n_vertex = pInChI->nConnTable[0] - 1; i < pInChI->lenConnTable; i++)
    {
        if (( n_neigh = pInChI->nConnTable[i] - 1 ) < n_vertex)
        {
            /*  vertex - neighbor connection */
            jv = at[n_vertex].valence++;
            at[n_vertex].neighbor[jv] = n_neigh;
            at[n_vertex].bond_type[jv] = BOND_TYPE_SINGLE;
            at[n_vertex].chem_bonds_valence += at[n_vertex].bond_type[jv];
            /*  neighbor - vertex connection */
            jn = at[n_neigh].valence++;
            at[n_neigh].neighbor[jn] = n_vertex;
            at[n_neigh].bond_type[jn] = BOND_TYPE_SINGLE;
            at[n_neigh].chem_bonds_valence += at[n_neigh].bond_type[jn];
        }
        else if (( n_vertex = n_neigh ) >= num_atoms)
        {
            ret = RI_ERR_PROGR;
            goto exit_function;
        }
    }

    INCHI_HEAPCHK

    /* isotopic atoms */
    if (pInChI->IsotopicAtom && pInChI->nNumberOfIsotopicAtoms)
    {
        for (i = 0; i < pInChI->nNumberOfIsotopicAtoms; i++)
        {
            n_vertex = pInChI->IsotopicAtom[i].nAtomNumber - 1;
            /* djb-rwth: fixing oss-fuzz issues #68742, #30956 */
            if (n_vertex < num_atoms)
            {
                at[n_vertex].iso_atw_diff = (char)pInChI->IsotopicAtom[i].nIsoDifference;
                at[n_vertex].num_iso_H[0] = (char)pInChI->IsotopicAtom[i].nNum_H;
                at[n_vertex].num_iso_H[1] = (char)pInChI->IsotopicAtom[i].nNum_D;
                at[n_vertex].num_iso_H[2] = (char)pInChI->IsotopicAtom[i].nNum_T;
            }
        }
        pStruct->bIsotopic |= 1;
    }

    INCHI_HEAPCHK

    /* tautomeric groups */
    if ((ret = GetTgroupInfoFromInChI( &pStruct->ti, at, NULL, pInChI ))) /* djb-rwth: addressing LLVM warning */
    {
        goto exit_function;
    }

    /* coordinates: data from unused members: pInChI->IsotopicTGroup and InChI->nNumberOfIsotopicTGroups */
    if (pInChI->IsotopicTGroup && !pInChI->nNumberOfIsotopicTGroups)
    {
        pStruct->pXYZ = (XYZ_COORD *) pInChI->IsotopicTGroup;
        pInChI->IsotopicTGroup = NULL;
    }

    /* stereo */
    if (pInChI->StereoIsotopic &&
        ( pInChI->StereoIsotopic->nNumberOfStereoBonds +
            pInChI->StereoIsotopic->nNumberOfStereoCenters ))
    {
        pStereo = pInChI->StereoIsotopic;
    }
    else if (pInChI->Stereo &&
        ( pInChI->Stereo->nNumberOfStereoBonds +
            pInChI->Stereo->nNumberOfStereoCenters ))
    {
        pStereo = pInChI->Stereo;
    }
    else
    {
        pStereo = NULL;
    }

    /* stereo2: Mobile-H in addition to Fixed-H*/
    pStereo2 = NULL;
    if (pInChIMobH && pInChIMobH->nNumberOfAtoms)
    {
        if (pInChIMobH->StereoIsotopic &&
            ( pInChIMobH->StereoIsotopic->nNumberOfStereoBonds +
                pInChIMobH->StereoIsotopic->nNumberOfStereoCenters ))
        {
            pStereo2 = pInChIMobH->StereoIsotopic;
        }
        else
        {
            if (pInChIMobH->Stereo &&
                ( pInChIMobH->Stereo->nNumberOfStereoBonds +
                  pInChIMobH->Stereo->nNumberOfStereoCenters ))
            {
                pStereo2 = pInChIMobH->Stereo;
            }
        }
    }

    INCHI_HEAPCHK

    num_stereo_bonds2 = 0; /* djb-rwth: removing redundant code */
    num_stereo_centers2 = 0; /* djb-rwth: removing redundant code */
    /* -- have already been done in the initialization --
       iDeletedH = 0;
       nNumDeletedH = 0;
    */
    if (pStereo || pStereo2)
    {
        /* count implicit H needed for parities and reallocate at[]; set at[n_vertex].at_type=1 for these atoms */
        int len1 = pStereo ? pStereo->nNumberOfStereoCenters : 0;
        int len2 = pStereo2 ? pStereo2->nNumberOfStereoCenters : 0;
        int i2, diff, diff2;
        for (i = i2 = 0; i < len1 || i2 < len2; )
        {
            if (i < len1 && i2 < len2)
            {
                diff = (int) pStereo->nNumber[i] - (int) pStereo2->nNumber[i2];
                if (diff <= 0)
                {
                    n_vertex = pStereo->nNumber[i] - 1;
                    i++;
                    i2 += !diff;
                }
                else
                {
                    n_vertex = pStereo2->nNumber[i2] - 1;
                    num_stereo_centers2++;
                    i2++;
                }
            }
            else if (i < len1)
            {
                n_vertex = pStereo->nNumber[i] - 1;
                i++;
            }
            else
            {
                n_vertex = pStereo2->nNumber[i2] - 1;
                num_stereo_centers2++;
                i2++;
            }

            jv = at[n_vertex].neighbor[0]; /* djb-rwth: avoiding unsequenced modification and access */
            jn = at[n_vertex].neighbor[1]; /* djb-rwth: avoiding unsequenced modification and access */
            /* find whether it is an allene */
            if (at[n_vertex].valence == 2 &&
                 at[n_vertex].num_H == 0 &&
                 bCanAtomBeMiddleAllene( at[n_vertex].elname, 0, 0 ) &&
                 at[jv].valence + at[jv].num_H == 3 &&
                 bCanAtomBeTerminalAllene( at[jv].elname, 0, 0 ) &&
                 at[jn].valence + at[jn].num_H == 3 &&
                 bCanAtomBeTerminalAllene( at[jn].elname, 0, 0 ))
            {
                /* allene */
                if (!at[jv].at_type && at[jv].num_H)
                {
                    nNumDeletedH += at[jv].num_H;
                    at[jv].at_type++;  /* H should be added as an explicit H */
                }

                if (!at[jn].at_type && at[jn].num_H)
                {
                    nNumDeletedH += at[jn].num_H;
                    at[jn].at_type++;  /* H should be added as an explicit H */
                }
            }
            else
            {
                /* stereogenic atom - sp3 */
                if (!at[n_vertex].at_type && at[n_vertex].num_H)
                {
                    nNumDeletedH += at[n_vertex].num_H;
                    at[n_vertex].at_type++; /* H should be added as an explicit H */
                }
            }
        }

        INCHI_HEAPCHK

        len1 = pStereo ? pStereo->nNumberOfStereoBonds : 0;
        len2 = pStereo2 ? pStereo2->nNumberOfStereoBonds : 0;
        for (i = i2 = 0; i < len1 || i2 < len2; )
        {
            if (i < len1 && i2 < len2)
            {
                diff = (int) pStereo->nBondAtom1[i] - (int) pStereo2->nBondAtom1[i2];
                diff2 = (int) pStereo->nBondAtom2[i] - (int) pStereo2->nBondAtom2[i2];
                if (diff < 0 || (diff == 0 && diff2 <= 0)) /* djb-rwth: addressing LLVM warning */
                {
                    n_vertex = pStereo->nBondAtom1[i] - 1;
                    n_neigh = pStereo->nBondAtom2[i] - 1;
                    i++;
                    i2 += !diff && !diff2;
                }
                else
                {
                    n_vertex = pStereo2->nBondAtom1[i2] - 1;
                    n_neigh = pStereo2->nBondAtom2[i2] - 1;
                    num_stereo_bonds2++;
                    i2++;
                }
            }
            else if (i < len1)
            {
                n_vertex = pStereo->nBondAtom1[i] - 1;
                n_neigh = pStereo->nBondAtom2[i] - 1;
                i++;
            }
            else
            {
                n_vertex = pStereo2->nBondAtom1[i2] - 1;
                n_neigh = pStereo2->nBondAtom2[i2] - 1;
                num_stereo_bonds2++;
                i2++;
            }

            /* djb-rwth: fixing oss-fuzz issue #67650 */
            if ((n_vertex < num_atoms) && !is_in_the_list( at[n_vertex].neighbor,
                (AT_NUMB) n_neigh, at[n_vertex].valence ))
            {
                /* must be a cumulene */
                if (!bFindCumuleneChain( at, (AT_NUMB) n_vertex, (AT_NUMB) n_neigh,
                    nCumulene, MAX_CUMULENE_LEN + 1 ))
                {
                    ret = RI_ERR_SYNTAX; /* not a cumulene */
                    goto exit_function;
                }
            }

            if ((n_vertex < num_atoms) && !at[n_vertex].at_type && at[n_vertex].num_H)
            {
                nNumDeletedH += at[n_vertex].num_H;
                at[n_vertex].at_type++;  /* H should be added as an explicit H */
            }

            if (!at[n_neigh].at_type && at[n_neigh].num_H)
            {
                nNumDeletedH += at[n_neigh].num_H;
                at[n_neigh].at_type++;   /* H should be added as an explicit H */
            }
        }

        INCHI_HEAPCHK

        if (nNumDeletedH)
        {
            /* add explicit H */
#if ( FIX_GAF_2019_2==1 )           
            inp_ATOM *at2 = (inp_ATOM *)inchi_calloc(nNumDeletedH>0 ? num_atoms + nNumDeletedH : num_atoms,
                sizeof(at2[0]));
#else
            /* add explicit H */
            inp_ATOM *at2 = (inp_ATOM *)inchi_calloc(num_atoms + nNumDeletedH, sizeof(at2[0]));
#endif
            if (!at2)
            {
                ret = RI_ERR_ALLOC;
                goto exit_function;
            }
            pStruct->num_deleted_H = nNumDeletedH;
#if USE_BCF
            memcpy_s( at2, sizeof(at2[0])*num_atoms, at, num_atoms * sizeof(at2[0])); /* djb-rwth: function replaced with its safe C11 variant */
#else
            memcpy(at2, at, num_atoms * sizeof(at2[0]));
#endif
            inchi_free( at );
            pStruct->at = at = at2;
            /* fill out deleted H atom info */
            for (i = num_atoms; i < num_atoms + nNumDeletedH; i++)
            {
                /* djb-rwth: ui_rr */
                strcpy( at[i].elname, "H" );
                at[i].el_number = EL_NUMBER_H;
                at[i].orig_at_number = iAtNoOffset + i + 1;
                at[i].orig_compt_at_numb = i + 1;
                at[i].component = iComponent + 1;
            }

            /* connect deleted H */
            for (i = 0; i < num_atoms; i++)
            {
                if (at[i].at_type == 1)
                {
                    if (0 > ( ret = AddExplicitDeletedH( at, i, num_atoms,
                        &iDeletedH, &idelH1,
                        nNumDeletedH, pStereo2 != NULL ) ))
                    {
                        goto exit_function;
                    }
                }
            }
        }

        INCHI_HEAPCHK
    }

    if (pStereo)
    {
        /* mark stereo centers, they have already been connected the added explicit H, if any */
        int bInvertedParity = ( pStereo->nCompInv2Abs == -1 );
        for (i = 0; i < pStereo->nNumberOfStereoCenters; i++)
        {
            n_vertex = pStereo->nNumber[i] - 1;
            parity = pStereo->t_parity[i];
            if (bInvertedParity)
            {
                parity = ( parity == AB_PARITY_EVEN ) ? AB_PARITY_ODD : ( parity == AB_PARITY_ODD ) ? AB_PARITY_EVEN : parity;
            }
            /* find whether it is allene */
            if (at[n_vertex].valence == 2 &&
                 at[n_vertex].num_H == 0 &&
                 bCanAtomBeMiddleAllene( at[n_vertex].elname, 0, 0 ) &&
                 /* allene has exactly 2 double bonds */
                 ( jv = at[n_vertex].neighbor[0], at[jv].valence + at[jv].num_H == 3 ) &&
                 bCanAtomBeTerminalAllene( at[jv].elname, 0, 0 ) &&
                 ( jn = at[n_vertex].neighbor[1], at[jn].valence + at[jn].num_H == 3 ) &&
                 bCanAtomBeTerminalAllene( at[jn].elname, 0, 0 ))
            {
                /* allene: add explicit H if implicit H are present */
                /* iDeletedH = current number of already added explicit H */
                /* idelH1    = index in at[] of the explicit H added to atom jv */
                if (at[jv].num_H)
                {
                    if (0 > ( ret = AddExplicitDeletedH( at, jv, num_atoms, &iDeletedH,
                        &idelH1, nNumDeletedH,
                        pStereo2 != NULL ) ))
                    {
                        goto exit_function;
                    }
                }
                else
                {
                    /* index of the stereo atom neighbor */
                    idelH1 = at[jv].neighbor[at[jv].neighbor[0] == n_vertex];
                }

                if (at[jn].num_H)
                {
                    /* iDeletedH = current number of already added explicit H */
                    /* idelH2    = index of the explicit H added to atom jn */
                    if (0 > ( ret = AddExplicitDeletedH( at, jn, num_atoms, &iDeletedH, &idelH2, nNumDeletedH, pStereo2 != NULL ) ))
                    {
                        goto exit_function;
                    }
                }
                else
                {
                    idelH2 = at[jn].neighbor[at[jn].neighbor[0] == n_vertex];
                }
                /* allene: set bond types to double */
                /*
                if ( 0 > (ret = set_bond_type( at, (AT_NUMB)n_vertex, (AT_NUMB)jv, BOND_TYPE_DOUBLE ) ) ||
                     0 > (ret = set_bond_type( at, (AT_NUMB)n_vertex, (AT_NUMB)jn, BOND_TYPE_DOUBLE ) ) ) {
                    goto exit_function;
                }
                */
                /* allene: make 0D parity */
                ret = set_cumulene_0D_parity( at, st, num_atoms, idelH1, jv, jn, idelH2, parity, 2 );
                if (ret < 0)
                {
                    goto exit_function;
                }
            }
            else
            {
                /* stereogenic sp3 atom */
                if (at[n_vertex].num_H)
                {
                    if (0 > ( ret = AddExplicitDeletedH( at, n_vertex, num_atoms,
                        &iDeletedH, &idelH1, nNumDeletedH,
                        pStereo2 != NULL ) ))
                    {
                        goto exit_function;
                    }
                }

                ret = set_atom_0D_parity( at, st, num_atoms, nNumDeletedH, n_vertex, parity );

                if (ret < 0)
                {
                    goto exit_function;
                }
                /* djb-rwth: removing redundant code */
            }

            if (ret < 0)
            {
                goto exit_function;
            }
        }

        INCHI_HEAPCHK

        /* mark stereobonds */
        for (i = 0; i < pStereo->nNumberOfStereoBonds; i++)
        {
            jv = pStereo->nBondAtom1[i] - 1;
            jn = pStereo->nBondAtom2[i] - 1;
            parity = pStereo->b_parity[i];
            if (!is_in_the_list( at[jv].neighbor, (AT_NUMB) jn, at[jv].valence ))
            {
                /* must be a cumulene */
                if (!bFindCumuleneChain( at, (AT_NUMB) jv, (AT_NUMB) jn, nCumulene, MAX_CUMULENE_LEN + 1 ))
                {
                    return RI_ERR_SYNTAX; /* not a cumulene */
                }
                len = MAX_CUMULENE_LEN + 1;
            }
            else
            {
                /* a regular double or alt bond */
                nCumulene[0] = jv;
                nCumulene[1] = jn;
                len = 1; /* cumulene length is number of bonds, not number of atoms */
            }

            /* cumulene or double bond: add explicit H if implicit H are present */
            if (at[jv].num_H)
            {
                if (0 > ( ret = AddExplicitDeletedH( at, jv, num_atoms, &iDeletedH, &idelH1, nNumDeletedH, pStereo2 != NULL ) ))
                {
                    goto exit_function;
                }
            }
            else
            {
                /* double bond neighbor that has the smallest canonical number; it is either 0th or 1st */
                idelH1 = at[jv].neighbor[at[jv].neighbor[0] == nCumulene[1]];
            }
            if (at[jn].num_H)
            {
                if (0 > ( ret = AddExplicitDeletedH( at, jn, num_atoms, &iDeletedH, &idelH2, nNumDeletedH, pStereo2 != NULL ) ))
                {
                    goto exit_function;
                }
            }
            else
            {
                idelH2 = at[jn].neighbor[at[jn].neighbor[0] == nCumulene[len - 1]];
            }
            if (0 > ( ret = set_cumulene_0D_parity( at, st, num_atoms, idelH1, jv, jn, idelH2, parity, len ) ))
            {
                goto exit_function;
            }
        }

        INCHI_HEAPCHK
    }

    /* allocate memory for Mobile-H-only stereo */
    if (num_stereo_centers2 + num_stereo_bonds2)
    {
        if (!( st = (inp_ATOM_STEREO *) inchi_calloc( num_atoms, sizeof( st[0] ) ) ))
        {
            ret = RI_ERR_ALLOC;
            goto exit_function;
        }
        CopyAt2St( at, st, num_atoms );
    }

    pStruct->st = st;
    if (num_stereo_centers2)
    {
        /* In case of Fixed-H */
        /* mark additional Mobile-H stereo centers, they have already been connected the added explicit H, if any */
        int bInvertedParity = ( pStereo2->nCompInv2Abs == -1 );
        for (i = 0; i < pStereo2->nNumberOfStereoCenters; i++)
        {
            n_vertex = pStereo2->nNumber[i] - 1;
            parity = pStereo2->t_parity[i];
            if (at[n_vertex].p_parity)
            {
                continue; /* the parity has already been set for Fixed-H */
            }
            if (bInvertedParity)
            {
                parity = ( parity == AB_PARITY_EVEN ) ? AB_PARITY_ODD : ( parity == AB_PARITY_ODD ) ? AB_PARITY_EVEN : parity;
            }
            /* find whether it is allene */
            if (at[n_vertex].valence == 2 &&
                 at[n_vertex].num_H == 0 &&
                 bCanAtomBeMiddleAllene( at[n_vertex].elname, 0, 0 ) &&
                 /* allene has exactly 2 double bonds */
                 ( jv = at[n_vertex].neighbor[0], at[jv].valence + at[jv].num_H == 3 ) &&
                 bCanAtomBeTerminalAllene( at[jv].elname, 0, 0 ) &&
                 ( jn = at[n_vertex].neighbor[1], at[jn].valence + at[jn].num_H == 3 ) &&
                 bCanAtomBeTerminalAllene( at[jn].elname, 0, 0 ))
            {
                /* allene: add explicit H if implicit H are present */
                /* iDeletedH = current number of already added explicit H */
                /* idelH1    = index in at[] of the explicit H added to atom jv */
                if (at[jv].num_H)
                {
                    if (0 > ( ret = AddExplicitDeletedH( at, jv, num_atoms, &iDeletedH, &idelH1, nNumDeletedH, pStereo2 != NULL ) ))
                    {
                        goto exit_function;
                    }
                }
                else
                {
                    /* index of the stereo atom neighbor */
                    idelH1 = at[jv].neighbor[at[jv].neighbor[0] == n_vertex];
                }
                if (at[jn].num_H)
                {
                    /* iDeletedH = current number of already added explicit H */
                    /* idelH2    = index of the explicit H added to atom jn */
                    if (0 > ( ret = AddExplicitDeletedH( at, jn, num_atoms, &iDeletedH, &idelH2, nNumDeletedH, pStereo2 != NULL ) ))
                    {
                        goto exit_function;
                    }
                }
                else
                {
                    idelH2 = at[jn].neighbor[at[jn].neighbor[0] == n_vertex];
                }
                /* allene: set bond types to double */
                /*
                if ( 0 > (ret = set_bond_type( at, (AT_NUMB)n_vertex, (AT_NUMB)jv, BOND_TYPE_DOUBLE ) ) ||
                     0 > (ret = set_bond_type( at, (AT_NUMB)n_vertex, (AT_NUMB)jn, BOND_TYPE_DOUBLE ) ) ) {
                    goto exit_function;
                }
                */
                /* allene: make 0D parity */
                ret = set_cumulene_0D_parity( at, st, num_atoms, idelH1, jv, jn, idelH2, parity, 2 );
                if (ret < 0)
                {
                    goto exit_function;
                }
            }
            else
            {
                /* stereogenic sp3 atom */
                if (at[n_vertex].num_H)
                {
                    if (0 > ( ret = AddExplicitDeletedH( at, n_vertex, num_atoms, &iDeletedH, &idelH1, nNumDeletedH, pStereo2 != NULL ) ))
                    {
                        goto exit_function;
                    }
                }
                ret = set_atom_0D_parity( at, st, num_atoms, nNumDeletedH, n_vertex, parity );
                if (ret < 0)
                {
                    goto exit_function;
                }
                /* djb-rwth: removing redundant code */
            }
            if (ret < 0)
            {
                goto exit_function;
            }
        }
    }

    if (num_stereo_bonds2)
    {
        /* In case of Fixed-H */
        /* mark additional Mobile-H stereobonds, they have already been connected the added explicit H, if any */
        for (i = 0; i < pStereo2->nNumberOfStereoBonds; i++)
        {
            jv = pStereo2->nBondAtom1[i] - 1;
            jn = pStereo2->nBondAtom2[i] - 1;
            parity = pStereo2->b_parity[i];
            if (!is_in_the_list( at[jv].neighbor, (AT_NUMB) jn, at[jv].valence ))
            {
                /* must be a cumulene */
                if (!bFindCumuleneChain( at, (AT_NUMB) jv, (AT_NUMB) jn, nCumulene, MAX_CUMULENE_LEN + 1 ))
                {
                    return RI_ERR_SYNTAX; /* not a cumulene */
                }
                len = MAX_CUMULENE_LEN + 1;
            }
            else
            {
                /* a regular double or alt bond */
                nCumulene[0] = jv;
                nCumulene[1] = jn;
                len = 1; /* cumulene length is number of bonds, not number of atoms */
            }
            /* cumulene or double bond: add explicit H if implicit H are present */
            if (at[jv].num_H)
            {
                if (0 > ( ret = AddExplicitDeletedH( at, jv, num_atoms, &iDeletedH, &idelH1, nNumDeletedH, pStereo2 != NULL ) ))
                {
                    goto exit_function;
                }
            }
            else
            {
                /* double bond neighbor that has the smallest canonical number */
                idelH1 = at[jv].neighbor[at[jv].neighbor[0] == nCumulene[1]];
            }
            if (at[jn].num_H)
            {
                if (0 > ( ret = AddExplicitDeletedH( at, jn, num_atoms, &iDeletedH, &idelH2, nNumDeletedH, pStereo2 != NULL ) ))
                {
                    goto exit_function;
                }
            }
            else
            {
                idelH2 = at[jn].neighbor[at[jn].neighbor[0] == nCumulene[len - 1]];
            }
            if (0 > ( ret = set_cumulene_0D_parity( at, st, num_atoms, idelH1, jv, jn, idelH2, parity, len ) ))
            {
                goto exit_function;
            }
        }
    }

    ret = num_atoms;

exit_function:

    return ret;
}


/****************************************************************************/
int SetStereoBondTypeFor0DParity( inp_ATOM *at, int i1, int m1 )
{
    AT_NUMB nCumulene[MAX_CUMULENE_LEN + 2];
    int j, n1, n2, k1, m2, ret, nLenCumulene = 0, bond_type;
    k1 = at[i1].sb_ord[m1];
    n1 = i1;
    nCumulene[nLenCumulene++] = n1;
    do
    {
        n2 = at[n1].neighbor[k1]; /* next atom */
        nCumulene[nLenCumulene++] = n2;
        for (m2 = 0; m2 < MAX_NUM_STEREO_BONDS && at[n2].sb_parity[m2]; m2++)
        {
            if (n1 == at[n2].neighbor[(int) at[n2].sb_ord[m2]])
            {
                /* found the endatom */
                goto found;
            }
        }
        if (at[n2].num_H || at[n2].valence != 2 || at[n2].endpoint)
        {
            break; /* not a middle cumulene */
        }
        k1 = ( at[n2].neighbor[0] == n1 );
        n1 = n2;
    }
    while (at[n1].valence == 2 && !at[n1].num_H && nLenCumulene < MAX_CUMULENE_LEN + 2 &&
           bCanAtomBeMiddleAllene( at[n1].elname, at[n1].charge, at[n1].radical ));
    return RI_ERR_SYNTAX; /* failed */

found:
    if (nLenCumulene == 2)
    {
        bond_type = BOND_TYPE_STEREO; /* double bond or alternating bond */
    }
    else
    {
        bond_type = BOND_TYPE_DOUBLE; /* cumulene or allene */
    }

    for (j = 1; j < nLenCumulene; j++)
    {
        /* if bond_type = BOND_TYPE_DOUBLE then increments at->cham_bonds_valence: */
        /* at->cham_bonds_valence += BOND_TYPE_DOUBLE-BOND_TYPE_SINGLE */
        if (0 > ( ret = set_bond_type( at, (AT_NUMB) nCumulene[j - 1], (AT_NUMB) nCumulene[j], bond_type ) )) /* djb-rwth: ignoring LLVM warning: variable used to store function return value */
        {
            return RI_ERR_PROGR; /* failed */
        }
    }
    return nLenCumulene;
}


/****************************************************************************/
int SetStereoBondTypesFrom0DStereo( StrFromINChI *pStruct, INChI *pInChI )
{
    INChI_Stereo *pStereo;
    inp_ATOM     *at = pStruct->at;
    int           num_atoms = pStruct->num_atoms;
    int           i, j, num_stereo_bonds, ret;

    if (pInChI->StereoIsotopic &&
        ( pInChI->StereoIsotopic->nNumberOfStereoBonds +
            pInChI->StereoIsotopic->nNumberOfStereoCenters ))
    {
        pStereo = pInChI->StereoIsotopic;
    }
    else
        if (pInChI->Stereo &&
            ( pInChI->Stereo->nNumberOfStereoBonds +
                pInChI->Stereo->nNumberOfStereoCenters ))
        {
            pStereo = pInChI->Stereo;
        }
        else
        {
            pStereo = NULL;
        }

    /************************ set bond types separately from stereo *******************/
    if (pStereo)
    {
        num_stereo_bonds = 0;
        for (i = 0; i < num_atoms; i++)
        {
            /* set BOND_TYPE_DOUBLE in allenes and cumulenes */
            /* set BOND_TYPE_STEREO in double bond stereo */
            for (j = 0; j < MAX_NUM_STEREO_BONDS && at[i].sb_parity[j]; j++)
            {
                num_stereo_bonds++;
                if (0 > ( ret = SetStereoBondTypeFor0DParity( at, i, j ) ))
                {
                    goto exit_function;
                }
            }
        }
        if (num_stereo_bonds)
        {
            int num_bond_type_stereo;
            int num_bond_type_altern;
            AT_NUMB neigh;
            /* replace adjacent BOND_TYPE_STEREO with BOND_TYPE_ALTERN */
            for (i = 0; i < num_atoms; i++)
            {
                num_bond_type_stereo = 0;
                num_bond_type_altern = 0;
                for (j = 0; j < at[i].valence; j++)
                {
                    num_bond_type_stereo += ( at[i].bond_type[j] == BOND_TYPE_STEREO );
                    num_bond_type_altern += ( at[i].bond_type[j] == BOND_TYPE_ALTERN );
                }
                if (num_bond_type_stereo + num_bond_type_altern > 1 && num_bond_type_stereo)
                {
                    for (j = 0; j < at[i].valence; j++)
                    {
                        if (at[i].bond_type[j] == BOND_TYPE_STEREO)
                        {
                            neigh = at[i].neighbor[j];
                            /* does not change at[i].chem_bond_valence in case of BOND_TYPE_ALTERN */
                            if (0 > ( ret = set_bond_type( at, (AT_NUMB) i, neigh, BOND_TYPE_ALTERN ) ))
                            {
                                goto exit_function;
                            }
                        }
                    }
                }
                /* at this point only isolated stereo bonds have type BOND_TYPE_STEREO */
            }
            /* increment at[i].chem_bonds_valence if at[i] has an altern. bond */
            /* replace BOND_TYPE_STEREO with BOND_TYPE_DOUBLE and increment   */
            /* chem_bonds_valence of the adjacent atoms */
            for (i = 0; i < num_atoms; i++)
            {
                num_bond_type_stereo = 0;
                num_bond_type_altern = 0;
                for (j = 0; j < at[i].valence; j++)
                {
                    num_bond_type_stereo += ( at[i].bond_type[j] == BOND_TYPE_STEREO );
                    num_bond_type_altern += ( at[i].bond_type[j] == BOND_TYPE_ALTERN );
                }
                if (!num_bond_type_stereo && num_bond_type_altern)
                {
                    /* an atom has only BOND_TYPE_ALTERN => adjacent BOND_TYPE_ALTERN case */
                    at[i].chem_bonds_valence += 1;
                }
                else
                {
                    if (num_bond_type_stereo == 1)
                    {
                        /* isolated BOND_TYPE_STEREO => replace with BOND_TYPE_DOUBLE */
                        for (j = 0; j < at[i].valence; j++)
                        {
                            if (at[i].bond_type[j] == BOND_TYPE_STEREO)
                            {
                                neigh = at[i].neighbor[j];
                                /* replacing BOND_TYPE_STEREO with BOND_TYPE_DOUBLE */
                                /* does not change at->chem_bonds_valence */
                                if (0 > ( ret = set_bond_type( at, (AT_NUMB) i, neigh, BOND_TYPE_DOUBLE ) ))
                                {
                                    goto exit_function;
                                }
                                at[i].chem_bonds_valence++;
                                at[(int) neigh].chem_bonds_valence++;
                            }
                        }
                    }
                    else
                    {
                        if (num_bond_type_stereo + num_bond_type_altern)
                        {
                            /* an atom still has both BOND_TYPE_STEREO and BOND_TYPE_ALTERN */
                            ret = RI_ERR_PROGR;
                            goto exit_function;
                        }
                    }
                }
            }
            INCHI_HEAPCHK
        }
    }
    ret = 0; /* success */

exit_function:

    return ret;
}


/****************************************************************************/
int CopyBnsToAtom( StrFromINChI *pStruct,
                   BN_STRUCT  *pBNS,
                   VAL_AT *pVA,
                   ALL_TC_GROUPS *pTCGroups,
                   int bAllowZeroBondOrder )
{
    int i, j, charge, ret = 0, v1, nMinorder; /* djb-rwth: removing redundant variables */
    int          num_at = pStruct->num_atoms;
    inp_ATOM *at = pStruct->at;
    ICHICONST SRM *pSrm = pStruct->pSrm;
    BNS_VERTEX  *pv;
    BNS_EDGE    *pe;
    int          chem_bonds_valence, bond_order;

    /* djb-rwth: removing redundant code */
    for (i = 0; i < num_at; i++)
    {
        pv = pBNS->vert + i;
        /* bonds */
        chem_bonds_valence = 0;
        for (j = 0; j < at[i].valence; j++)
        {
            pe = pBNS->edge + pv->iedge[j];
            BondFlowMaxcapMinorder( at, pVA, pSrm, i, j, NULL, &nMinorder, NULL );
            bond_order = pe->flow + nMinorder;
            if (!bAllowZeroBondOrder && !bond_order)
            {
                bond_order = 1;
            }
            chem_bonds_valence += bond_order;
            at[i].bond_type[j] = bond_order;  /* BOND_MARK_HIGHLIGHT */
        }
        at[i].chem_bonds_valence = chem_bonds_valence;
        /* charges (both may be present resulting in zero) */
        at[i].charge = pVA[i].cInitCharge;
        if (pVA[i].nCMinusGroupEdge)
        {
            pe = pBNS->edge + pVA[i].nCMinusGroupEdge - 1;
            if ((charge = pe->flow)) /* djb-rwth: addressing LLVM warning */
            {
                at[i].charge -= charge;
                /* djb-rwth: removing redundant code */
            }
        }
        if (pVA[i].nCPlusGroupEdge)
        {
            pe = pBNS->edge + pVA[i].nCPlusGroupEdge - 1;
            if ((charge = pe->cap - pe->flow)) /* djb-rwth: addressing LLVM warning */
            {
                at[i].charge += charge;
                /* djb-rwth: removing redundant code */
            }
        }
        if (pv->st_edge.cap > pv->st_edge.flow)
        {
            at[i].radical = RADICAL_SINGLET + ( pv->st_edge.cap - pv->st_edge.flow );
        }
    }
    /* find charge excess */
    /* djb-rwth: removing redundant variables/code */
    /* tautomeric H and (-) */
    for (i = 0; i < pBNS->num_t_groups; i++)
    {
        /* tautomeric groups are first non-atom vertices;
        order of them is same as in pTCGroups->pTCG[] */
        int num_H = pTCGroups->pTCG[i].tg_num_H;
        int num_Minus = pTCGroups->pTCG[i].tg_num_Minus;
        int bMinusFirst = ( pTCGroups->pTCG[i].tg_RestoreFlags & TGRF_MINUS_FIRST );
        int num_at_add;
        Vertex vMinus = NO_VERTEX;
        pv = pBNS->vert + num_at + i;  /* t-group vertex */
        if (!( pv->type & BNS_VERT_TYPE_TGROUP ))
        {
            return RI_ERR_PROGR;
        }
        if (pTCGroups->pTCG[i].tg_set_Minus > 0 && num_Minus > 0)
        {
            vMinus = pTCGroups->pTCG[i].tg_set_Minus - 1;
            num_Minus--;
        }

        if (bMinusFirst)
        {
            for (j = 0; j < pv->num_adj_edges; j++)
            {
                pe = pBNS->edge + pv->iedge[j];
                v1 = pe->neighbor1;
                num_at_add = pe->flow;
                if (v1 == vMinus)
                {
                    if (num_at_add)
                    {
                        at[v1].charge = -1;  /* no checking at[v1].charge == 0 for now ??? */
                        num_at_add--;       /* no checking  num_at_add > 0 for now ??? */
                    }
                    else
                    {
                        num_Minus++;        /* error ??? */
                    }
                    vMinus = NO_VERTEX;
                }
                if (num_at_add > 0)
                {
                    /* atom has tautomeric attachment; do not allow =N(-) */
                    if (num_Minus && !at[v1].charge &&
                         at[v1].valence == at[v1].chem_bonds_valence)
                    {
                        at[v1].charge--;
                        num_at_add--;
                        num_Minus--;
                    }
                    if (num_at_add > 0)
                    {
                        at[v1].num_H += num_at_add;
                        num_H -= num_at_add;
                        /* djb-rwth: removing redundant code */
                    }
                }
                at[v1].endpoint = i + 1;
            }
            if (( num_H + num_Minus != pv->st_edge.cap - pv->st_edge.flow ) && ( num_H || num_Minus || vMinus != NO_VERTEX ))
            {
                return RI_ERR_PROGR;
            }
        }
        else
        {
            for (j = pv->num_adj_edges - 1; 0 <= j; j--)
            {
                pe = pBNS->edge + pv->iedge[j];
                v1 = pe->neighbor1;
                num_at_add = pe->flow;
                if (v1 == vMinus)
                {
                    if (num_at_add)
                    {
                        at[v1].charge = -1;  /* no checking at[v1].charge == 0 for now ??? */
                        num_at_add--;       /* no checking  num_at_add > 0 for now ??? */
                    }
                    else
                    {
                        num_Minus++;        /* error ??? */
                    }
                    vMinus = NO_VERTEX;
                }
                if (num_at_add > 0)
                {
                    /* atom has tautomeric attachment; do not allow =N(-) */
                    if (num_Minus && !at[v1].charge &&
                         at[v1].valence == at[v1].chem_bonds_valence)
                    {
                        at[v1].charge--;
                        num_at_add--;
                        num_Minus--;
                    }
                    if (num_at_add > 0)
                    {
                        at[v1].num_H += num_at_add;
                        num_H -= num_at_add;
                        /* djb-rwth: removing redundant code */
                    }
                }
                at[v1].endpoint = i + 1;
            }
            if (( num_H + num_Minus != pv->st_edge.cap - pv->st_edge.flow ) && ( num_H || num_Minus || vMinus != NO_VERTEX ))
            {
                return RI_ERR_PROGR;
            }
        }
    }

    return ret;
}


/****************************************************************************/
int CheckBnsConsistency( StrFromINChI *pStruct,
                         BN_STRUCT  *pBNS,
                         VAL_AT *pVA,
                         ALL_TC_GROUPS *pTCGroups,
                         int bNoRad )
{
    int nOutput = 0;
#ifndef TARGET_API_LIB
#if ( bRELEASE_VERSION == 0 )
    char s[128];
    int i, j, atom_charge, left_charge, charge, excess_charge, ret = 0;
    int v1, v2, flow, tot_st_flow, tot_st_cap, num_electrons, nNumMetalAtoms;
    int       num_at = pStruct->num_atoms;
    inp_ATOM *at = pStruct->at;
    BNS_VERTEX  *pv;
    BNS_EDGE    *pe;
#ifdef _DEBUG
    int       bDebugOutput = 0;
    bNoRad = 1;
    bDebugOutput = 1;
#endif
    /* count electrons and metals */
    num_electrons = -pTCGroups->total_charge;
    nNumMetalAtoms = 0;
    for (i = 0; i < pTCGroups->num_tgroups; i++)
    {
        num_electrons += pTCGroups->pTCG[i].tg_num_H;
    }
    for (i = 0; i < num_at; i++)
    {
        num_electrons += at[i].el_number + at[i].num_H;
        nNumMetalAtoms += pVA[i].cMetal;
    }
    /* create output string */
    sprintf( s, "%d:%d%sM%02dv%da%de%db%d* ",
                bNoRad, pTCGroups->iComponent + 1, num_electrons % 2 ? "O" : "E", nNumMetalAtoms,
                pBNS->num_vertices, num_at, pBNS->num_edges, pBNS->num_bonds );


    tot_st_flow = tot_st_cap = 0;
    atom_charge = left_charge = 0;
    if (pBNS->num_atoms != num_at)
    {
        fprintf( stdout, "\n%sNum. atoms discrepancy: %d(BNS) vs. %d(at) ", s, pBNS->num_atoms, num_at );
        nOutput++;
    }
    /* check edges */
#ifdef _DEBUG
    if (bDebugOutput && bNoRad)
    {
        fprintf( stderr, "\n\n------begin------------------------------------------------\n" );
        fprintf( stderr, "\n\fedge    cap       flow     v1   v2\n\n" );
        /*                  xxxx xxxx/xxxx xxxx/xxxx xxxx xxxx    */
    }
#endif
    for (i = 0; i < pBNS->num_edges; i++)
    {
        pe = pBNS->edge + i;
        v1 = pe->neighbor1;
        v2 = v1 ^ pe->neighbor12;
        if (pe->cap < pe->flow || pe->flow < 0)
        {
            fprintf( stdout, "\n%sedge %d (%d-%d) has cap=%d flow=%d  ", s, i, v1, v2, pe->cap, pe->flow );
            nOutput++;
        }
#ifdef _DEBUG
        if (bDebugOutput && bNoRad)
        {
            /*                xxxx  xxxx/xxxx xxxx/xxxx xxxx xxxx    */
            fprintf( stderr, "%4d %4d/%-4d %4d/%-4d %4d %4d\n", i, pe->cap, pe->cap0, pe->flow, pe->flow0, v1, v2 );
        }
#endif
    }


    /* check vertices */
#ifdef _DEBUG
    if (bDebugOutput && bNoRad)
    {
        fprintf( stderr, "\n\fvert   st-cap   st-flow   type iedge : neigh\n\n" );
        /*                   xxxx xxxx/xxxx xxxx/xxxx 0xXXX xxxx : xxx    */
    }
#endif
    for (i = 0; i < pBNS->num_vertices; i++)
    {
        pv = pBNS->vert + i;
#ifdef _DEBUG
        if (bDebugOutput && bNoRad)
        {
            /*                   xxxx xxxx/xxxx xxxx/xxxx 0xXXX xxxx : xxx    */
            int j;
            const char *s;
            char sAtom[6];
            switch (pv->type)
            {
                case BNS_VERT_TYPE_ATOM:
                    sprintf( sAtom, "At %-2.2s", i < num_at ? at[i].elname : "??" );
                    s = sAtom;
                    break;
                case BNS_VERT_TYPE_ATOM | BNS_VERT_TYPE_ENDPOINT:
                    s = "Endpt";
                    break;
                case BNS_VT_C_POS:
                    s = "(+)  ";
                    break;
                case BNS_VT_C_NEG:
                    s = "(-)  ";
                    break;
                case BNS_VT_C_POS_C:
                    s = "(+C) ";
                    break;
                case BNS_VT_C_NEG_C:
                    s = "(-C) ";
                    break;
                case BNS_VT_C_POS_M:
                    s = "(+M) ";
                    break;
                case BNS_VT_C_NEG_M:
                    s = "(-M) ";
                    break;
                case BNS_VT_C_POS_ALL:
                    s = "(+)Sg";
                    break;
                case BNS_VT_C_NEG_ALL:
                    s = "(-)Sg";
                    break;
                case BNS_VT_M_GROUP:
                    s = "M-grp";
                    break;
                case BNS_VERT_TYPE__AUX | BNS_VERT_TYPE_TEMP:
                    s = "ChStr";
                    break;
                case BNS_VERT_TYPE__AUX:
                    s = "Yconn";
                    break;
                case BNS_VERT_TYPE_TGROUP:
                    s = "T-grp";
                    break;
                default:
                    s = "Unkn.";
                    break;
            }
            fprintf( stderr, "%4d %4d/%-4d %4d/%-4d 0x%03X %5s",
                                i, pv->st_edge.cap, pv->st_edge.cap0, pv->st_edge.flow, pv->st_edge.flow0,
                                pv->type, s );
            for (j = 0; j < pv->num_adj_edges; j++)
            {
                fprintf( stderr, " %2d", pv->iedge[j] );
            }
            fprintf( stderr, ":" );
            for (j = 0; j < pv->num_adj_edges; j++)
            {
                pe = pBNS->edge + pv->iedge[j];
                fprintf( stderr, " %2d", pe->neighbor12 ^ i );
            }
            fprintf( stderr, "\n" );
        }
#endif
        tot_st_flow += pv->st_edge.flow;
        tot_st_cap += pv->st_edge.cap;
        if (pv->num_adj_edges > pv->max_adj_edges)
        {
            fprintf( stdout, "\n%s%s %d type 0x%X \"%s\" num_edges=%d > max=%d  ", s,
                i < num_at ? "atom" : "vertex", i,
                pv->type, at[i].elname, pv->num_adj_edges, pv->max_adj_edges );
            nOutput++;
        }
        if (i < num_at)
        {
            /* charge on atoms */
            charge = pVA[i].cInitCharge;
            if (pVA[i].nCMinusGroupEdge)
            {
                pe = pBNS->edge + pVA[i].nCMinusGroupEdge - 1;
                if (pe->flow > 0)
                {
                    charge -= pe->flow;
                }
            }
            if (pVA[i].nCPlusGroupEdge)
            {
                pe = pBNS->edge + pVA[i].nCPlusGroupEdge - 1;
                if (pe->cap > pe->flow)
                {
                    charge += pe->cap - pe->flow;
                }
            }
            if (bNoRad && pv->st_edge.flow != pv->st_edge.cap)
            {
                fprintf( stdout, "\n%s%s %d: type 0x%X \"%s\" unexpected st_cap=%d st_flow=%d ", s,
                    i < num_at ? "atom" : "vertex", i,
                    pv->type, at[i].elname, pv->st_edge.cap, pv->st_edge.flow );
                nOutput++;
            }
            else
                if (bNoRad && charge && !strcmp( at[i].elname, "C" ))
                {
                    /* ignore carbonyls */
                    if (i == 0 && num_at == 2 && !strcmp( at[1].elname, "O" ) &&
                         !at[0].num_H && !at[1].num_H && !pTCGroups->total_charge)
                    {
                        ; /* C(-)#O(+) structure */
                    }
                    else
                    {
                        fprintf( stdout, "\n%s%s %d: type 0x%X \"%s\" charge=%d ", s,
                            i < num_at ? "atom" : "vertex", i,
                            pv->type, at[i].elname, charge );
                        nOutput++;
                    }
                }
            atom_charge += charge;
        }
        else
            if (( charge = pv->st_edge.cap - pv->st_edge.flow ) > 0)
            {
                /* excess charge */
                if (!bNoRad && IS_BNS_VT_C_OR_CSUPER_GR( pv->type ))
                {
                    left_charge -= charge;
                }
                else
                    if (!bNoRad && IS_BNS_VT_YVCONNECTOR( pv->type ))
                    {
                        left_charge += charge;
                    }
                    else
                        if (!bNoRad && IS_BNS_VT_M_GR( pv->type ) &&
                             0 <= ( j = pTCGroups->nGroup[TCG_MeFlower3] ) &&
                             i == pTCGroups->pTCG[j].nVertexNumber)
                        {
                            ; /* additional "radical" on metal flower */
                        }
                        else
                            if (!( pv->type & BNS_VERT_TYPE_TGROUP ) || bNoRad)
                            {
                                /* t-groups before running BFS should have st_cap > st_flow */
                                fprintf( stdout, "\n%s%s %d: type 0x%X unexpected st_cap=%d st_flow=%d ", s,
                                    i < num_at ? "atom" : "vertex", i,
                                    pv->type, pv->st_edge.cap, pv->st_edge.flow );
                                nOutput++;
                            }
            }
        if (pv->st_edge.cap < pv->st_edge.flow || pv->st_edge.flow < 0)
        {
            fprintf( stdout, "\n%s%s %d: type 0x%X \"%s\" st_cap=%d st_flow=%d  ", s,
                i < num_at ? "atom" : "vertex", i,
                pv->type, i < num_at ? at[i].elname : "", pv->st_edge.cap, pv->st_edge.flow );
            nOutput++;
        }
        /* check edge_flow vs. st_flow consistency */
        for (j = 0, flow = 0; j < pv->num_adj_edges; j++)
        {
            pe = pBNS->edge + pv->iedge[j];
            flow += pe->flow;
        }
        if (flow != pv->st_edge.flow)
        {
            fprintf( stdout, "\n%s%s %d: type 0x%X \"%s\" st_flow=%d edge_flow=%d  ", s,
                i < num_at ? "atom" : "vertex", i,
                pv->type, i < num_at ? at[i].elname : "", pv->st_edge.flow, flow );
            nOutput++;
        }
    }
#ifdef _DEBUG
    if (bDebugOutput && bNoRad)
    {
        fprintf( stderr, "\n------end--------------------------------------------------\n" );
    }
#endif
    /*
    if ( num_electrons %= 2 ) {
        fprintf( stdout, "\n%d*Odd number of electrons (%d atoms) ", bNoRad, num_at );
        nOutput ++;
    }
    */
    /* tautomeric groups charge */
    for (i = 0, charge = 0; i < pTCGroups->num_tgroups; i++)
    {
        charge -= pTCGroups->pTCG[i].tg_num_Minus;
    }
    /* compare */
    if (charge != pTCGroups->tgroup_charge)
    {
        fprintf( stdout, "\n%sCounted t-group charge=%d while %d was saved  ", s,
               charge, pTCGroups->tgroup_charge );
        nOutput++;
    }
    /* add other charges */
    charge += atom_charge + left_charge;
    excess_charge = pTCGroups->total_charge - pTCGroups->added_charge - pTCGroups->tgroup_charge;
    if (charge != pTCGroups->total_charge && excess_charge != pTCGroups->total_charge - charge)
    {
        fprintf( stdout, "\n%sCounted total charge=%d while %d was saved; excess charge=%d  ", s,
            charge, pTCGroups->total_charge, excess_charge );
        nOutput++;
    }
    if (tot_st_cap != pBNS->tot_st_cap || tot_st_flow != pBNS->tot_st_flow)
    {
        fprintf( stdout, "\n%sCounted/saved total st_flow=%d/%d st_cap=%d/%d  ", s,
            tot_st_flow, pBNS->tot_st_flow, tot_st_cap, pBNS->tot_st_cap );
        nOutput++;
    }
    if (nOutput)
    {
        fprintf( stdout, "\n" );
    }
#endif
#endif

    return nOutput;
}


/****************************************************************************/
int AddExplicitDeletedH( inp_ATOM *at,
                         int jv,
                         int num_at,
                         int *iDeletedH,
                         int *iH,
                         int nNumDeletedH,
                         int bTwoStereo )
{
    inp_ATOM  *cur_H, *cur_at = at + jv;
    int        tot_num_iso_H = NUM_ISO_H( cur_at, 0 );
    int        num_H = cur_at->num_H;
    int        iso_H = 0;
    S_CHAR     num_iso_H[NUM_H_ISOTOPES];
    int        i;

    if (!at[jv].at_type)
    {
        return RI_ERR_PROGR;
    }

    if (at[jv].at_type > 1)
    {
        /* explicit hydrogens have already been added; find them */
        for (i = 0; i < *iDeletedH; i++)
        {
            if (at[num_at + i].neighbor[0] == jv)
            {
                *iH = num_at + i; /* return the first found H, it has the smallest canonical pseudo rank */
                return 0;
            }
        }
        return RI_ERR_PROGR;
    }
    /* add all explicit H disconnected from at[jv] in order H, 1H, D, T */
    *iH = *iDeletedH + num_at; /* num_H includes all H, both isotopic and normal */
    for (i = 0; i < NUM_H_ISOTOPES; i++)
    {
        num_iso_H[i] = at[jv].num_iso_H[i];
    }
    for (; num_H && ( *iDeletedH ) < nNumDeletedH; ( *iDeletedH )++)
    {
        cur_H = at + num_at + ( *iDeletedH ); /* first available empty atom will be this explicit H */
        cur_H->neighbor[cur_H->valence] = jv; /* connect this new atom H to the real atom */
        cur_H->bond_type[cur_H->valence] = BOND_TYPE_SINGLE;
        cur_H->valence++;
        if (num_H > tot_num_iso_H)
        {
            num_H--;
            if (num_H != tot_num_iso_H)
            {
                /* may happen when Mobile-H stereo included in Fixed-H processing */
                if (bTwoStereo)
                {
                    continue;
                }
                else
                {
                    return RI_ERR_SYNTAX; /* two identical H neighbors of a stereo atom/bond */
                }
            }
        }
        else
        {
            while (iso_H < NUM_H_ISOTOPES && !num_iso_H[iso_H])
            {
                iso_H++;
            }
            if (iso_H < NUM_H_ISOTOPES)
            {
                cur_H->iso_atw_diff = iso_H + 1; /* isotopic shift + 1 */
                num_H--;
                tot_num_iso_H--;
                num_iso_H[iso_H] --;
                if (num_iso_H[iso_H])
                {
                    return RI_ERR_SYNTAX; /* two identical isotopic H neighbors of a stereo atom/bond */
                }
            }
            else
            {
                return RI_ERR_SYNTAX; /* not enough isotopic H */
            }
        }
    }
    if (num_H)
    {
        return RI_ERR_SYNTAX;
    }
    at[jv].at_type++; /* at[jv].at_type==2 => explicit hydrogens have already been added */

    return 0; /* success */
}


/****************************************************************************/
int bFindCumuleneChain( inp_ATOM *at,
                        AT_NUMB i1,
                        AT_NUMB i2,
                        AT_NUMB nCumulene[],
                            /* nCumulene[nMaxLen+1] will contain cumulene chain >i1=x=y=i2< in this order */
                        int nMaxLen )
                            /* nMaxLen = number of bonds in cumulene = 3 = MAX_CUMULENE_LEN+1 */

{
    int i, len, iat, nat;
    nCumulene[0] = i1;
    for (i = 0; i < at[i1].valence; i++)
    {
        len = 0;
        iat = i1; /* current */
        nat = at[i1].neighbor[i]; /* next */
        if (len + 1 == nMaxLen)
        {
            if (nat == i2)
            {
                nCumulene[++len] = nat;
                return 1; /* success */
            }
            continue; /* check next at[i1] neighbor */
        }
        while (at[nat].valence == 2 &&
                at[nat].num_H == 0 &&
                bCanAtomBeMiddleAllene( at[nat].elname, 0, 0 ))
        {
            nCumulene[++len] = nat;
            nat = at[nat].neighbor[at[nat].neighbor[0] == iat]; /* new next */
            if (len + 1 == nMaxLen)
            {
                if (nat == i2)
                {
                    nCumulene[++len] = nat;
                    return 1; /* success */
                }
                break; /* check next at[i1] neighbor */
            }
            iat = nCumulene[len]; /* new current */
        }
    }

    return 0; /* failed */
}


/****************************************************************************/
int set_bond_type( inp_ATOM *at, AT_NUMB i1, AT_NUMB i2, int bType )
{
    AT_NUMB *p1 = is_in_the_list( at[i1].neighbor, i2, at[i1].valence );
    AT_NUMB *p2 = is_in_the_list( at[i2].neighbor, i1, at[i2].valence );
    if (p1 && p2)
    {
        int j1 = (int) ( p1 - at[i1].neighbor );
        int j2 = (int) ( p2 - at[i2].neighbor );
        int bTypePrev = at[i1].bond_type[j1];
        at[i1].bond_type[j1] = bType;
        at[i2].bond_type[j2] = bType;
        if (bTypePrev && bTypePrev <= BOND_TYPE_TRIPLE &&
             bType     && bType <= BOND_TYPE_TRIPLE)
        {
            at[i1].chem_bonds_valence += bType - bTypePrev;
            at[i2].chem_bonds_valence += bType - bTypePrev;
        }
        return 0;
    }

    return RI_ERR_SYNTAX;
}


/****************************************************************************/
int set_cumulene_0D_parity( inp_ATOM *at,
                            inp_ATOM_STEREO *st,
                            int num_at,
                            int idelH1,
                            int i1,
                            int i2,
                            int idelH2,
                            int parity,
                            int len )
{
    AT_NUMB nCumulene[MAX_CUMULENE_LEN + 2];
    AT_NUMB *p1, *p2;
    int     m1, m2, parity1, parity2, sb_ord_m1, sb_ord_m2, k1, k2, num_neigh1, num_neigh2;
    /* the following types must exactly match types in inp_ATOM and inp_ATOM_STEREO */
    S_CHAR  *sb_ord1, *sn_ord1, *sb_parity1;
    S_CHAR  *sb_ord2, *sn_ord2, *sb_parity2;
    AT_NUMB *sn_orig_at_num1;
    AT_NUMB *sn_orig_at_num2;


    if (!bFindCumuleneChain( at, (AT_NUMB) i1, (AT_NUMB) i2, nCumulene, len ))
    {
        return RI_ERR_SYNTAX; /* not an allene */
    }
    /* stereo bond neighbors: index of a stereo bond in its end-atom adjacency lists */
    if (( p1 = is_in_the_list( at[i1].neighbor, nCumulene[1], at[i1].valence ) ) &&
        ( p2 = is_in_the_list( at[i2].neighbor, nCumulene[len - 1], at[i2].valence ) ))
    {
        sb_ord_m1 = (int) ( p1 - at[i1].neighbor ); /* indes of stereobond in the atom's adjacency list */
        sb_ord_m2 = (int) ( p2 - at[i2].neighbor );
    }
    else
    {
        return RI_ERR_PROGR;
    }
    num_neigh1 = at[i1].valence + at[i1].num_H;
    num_neigh2 = at[i2].valence + at[i2].num_H;

    if (num_neigh1 < MIN_NUM_STEREO_BOND_NEIGH || num_neigh1 > MAX_NUM_STEREO_BOND_NEIGH ||
         num_neigh2 < MIN_NUM_STEREO_BOND_NEIGH || num_neigh2 > MAX_NUM_STEREO_BOND_NEIGH)
    {
        return RI_ERR_SYNTAX;
    }


    sb_ord1 = st ? st[i1].sb_ord : at[i1].sb_ord;
    sb_ord2 = st ? st[i2].sb_ord : at[i2].sb_ord;
    sb_parity1 = st ? st[i1].sb_parity : at[i1].sb_parity;
    sb_parity2 = st ? st[i2].sb_parity : at[i2].sb_parity;

    /* find the first unoccupied locations in the stereobond 0D descriptor lists; check whether the stereo has already been set */
    for (m1 = k1 = 0; m1 < MAX_NUM_STEREO_BONDS && sb_parity1[m1] && !( k1 = sb_ord1[m1] == sb_ord_m1 ); m1++)
        ;
    for (m2 = k2 = 0; m2 < MAX_NUM_STEREO_BONDS && sb_parity2[m2] && !( k2 = sb_ord2[m2] == sb_ord_m2 ); m2++)
        ;
    if (m1 == MAX_NUM_STEREO_BONDS || m2 == MAX_NUM_STEREO_BONDS)
    {
        return RI_ERR_SYNTAX;
    }
    if (k1 && k2)
    {
        return 0; /* the stereo descriptor of this bond/allene/cumulene has already been set */
    }
    if (k1 || k2)
    {
        return RI_ERR_SYNTAX; /* only half of a bond was set */
    }

    sn_ord1 = st ? st[i1].sn_ord : at[i1].sn_ord;
    sn_ord2 = st ? st[i2].sn_ord : at[i2].sn_ord;
    sn_orig_at_num1 = st ? st[i1].sn_orig_at_num : at[i1].sn_orig_at_num;
    sn_orig_at_num2 = st ? st[i2].sn_orig_at_num : at[i2].sn_orig_at_num;

    /* stereo bond neighbors connection index */
    sb_ord1[m1] = sb_ord_m1;
    sb_ord2[m2] = sb_ord_m2;
    /* stereo bond end atom neighbors */
    sn_orig_at_num1[m1] = at[idelH1].orig_at_number;
    if (idelH1 < num_at)
    {
        if ((p1 = is_in_the_list( at[i1].neighbor, (AT_NUMB) idelH1, at[i1].valence ))) /* djb-rwth: addressing LLVM warning */
        {
            sn_ord1[m1] = (int) ( p1 - at[i1].neighbor );
        }
        else
        {
            return RI_ERR_PROGR;
        }
    }
    else
    {
        sn_ord1[m1] = -1;
    }

    sn_orig_at_num2[m2] = at[idelH2].orig_at_number;
    if (idelH2 < num_at)
    {
        if ((p2 = is_in_the_list( at[i2].neighbor, (AT_NUMB) idelH2, at[i2].valence ))) /* djb-rwth: addressing LLVM warning */
        {
            sn_ord2[m2] = (int) ( p2 - at[i2].neighbor );
        }
        else
        {
            return RI_ERR_PROGR;
        }
    }
    else
    {
        sn_ord2[m2] = -1;
    }
    if (ATOM_PARITY_WELL_DEF( parity ))
    {
        /* special case: 2 bonds to sb atom => inverse parity because */
        /* InChI parity refers to the lone pair as a neighbor */
        int num_inv = ( num_neigh1 == MIN_NUM_STEREO_BOND_NEIGH ) + ( num_neigh2 == MIN_NUM_STEREO_BOND_NEIGH );
        if (num_inv % 2)
        {
            parity = ( parity == AB_PARITY_EVEN ) ? AB_PARITY_ODD : AB_PARITY_EVEN;
        }
        parity1 = AB_PARITY_EVEN;
        parity2 = ( parity == AB_PARITY_EVEN ) ? AB_PARITY_EVEN : AB_PARITY_ODD;
    }
    else
    {
        parity1 = parity2 = parity;
    }
    sb_parity1[m1] = parity1;
    sb_parity2[m2] = parity2;

    return 0;
}


/****************************************************************************/
int set_atom_0D_parity( inp_ATOM *at,
                        inp_ATOM_STEREO *st,
                        int num_at,
                        int num_deleted_H,
                        int i1,
                        int parity )
{
    int     m1 = 0, m2, i, j, tot_num_neigh;
    /* the following types must exactly match types in inp_ATOM and inp_ATOM_STEREO */
    /* Given parity from InChI, the order of stereo center neighbors is: */
    /* 1. The stereocenter itself if the total number of neighbors is 3 (not 4) */
    /* 2. Explicit H: non-isotopic, isotopic in order ofascending  atomic mass */
    /*         Explicit H have already been sorted in this order */
    /* 3. Normal neighboring atoms, atom numbers (=canonical numbers from InChI - 1) in ascending order */
    /*         Normal neighboring atoms have already been sorted in this order */
    S_CHAR  *p_parity;
    AT_NUMB *p_orig_at_num;

    if (!st || !at[i1].p_parity)
    {
        m1 = 0;
        p_parity = st ? &st[i1].p_parity : &at[i1].p_parity;
        p_orig_at_num = st ? st[i1].p_orig_at_num : at[i1].p_orig_at_num;

        tot_num_neigh = at[i1].valence + at[i1].num_H;
        if (tot_num_neigh == MAX_NUM_STEREO_ATOM_NEIGH - 1)
        {
            /* only 3 neighbors: the atom itself is the first neighbor */
            p_orig_at_num[m1++] = at[i1].orig_at_number;
        }
        else
            if (tot_num_neigh != MAX_NUM_STEREO_ATOM_NEIGH)
            {
                return RI_ERR_PROGR; /* wrong number of members */
            }
        m2 = m1 + ( MAX_NUM_STEREO_ATOM_NEIGH - at[i1].valence );
        /* stereoneighbors: deleted explicit atoms H first, in order of increasing isotopic mass */
        if (at[i1].num_H)
        {
            for (j = 0; m1 < m2 && j < num_deleted_H; j++)
            {
                if (at[j + num_at].neighbor[0] == i1)
                {
                    p_orig_at_num[m1++] = at[j + num_at].orig_at_number;
                }
            }
        }
        if (m1 + at[i1].valence != MAX_NUM_STEREO_ATOM_NEIGH)
        {
            return RI_ERR_PROGR; /* wrong number of members */
        }
        /* stereoneighbors: other than explicit H atoms */
        for (i = 0; i < at[i1].valence; i++)
        {
            m2 = at[i1].neighbor[i];
            p_orig_at_num[m1++] = at[m2].orig_at_number;
        }
        *p_parity = parity;
    }

    return 0;
}


#if ( BNS_RAD_SEARCH == 1 )


/****************************************************************************/
int MoveRadToAtomsAddCharges( BN_STRUCT *pBNS,
                              BN_DATA *pBD,
                              StrFromINChI *pStruct,
                              inp_ATOM *at,
                              inp_ATOM *at2,
                              VAL_AT *pVA,
                              ALL_TC_GROUPS *pTCGroups,
                              int forbidden_mask )
{
    int nNumRad, ret = 0, ret2;
    int i, j, k, num_rad_not_atom, num_moved = 0, num_candidates = 0, extra_charge = 0, added_charge, delta;
    BNS_EDGE   *pEdge;
    BNS_VERTEX *pv;
    Vertex      v1, v2;
    S_SHORT    *pnRad = NULL, *pnDelta = NULL;
    CC_CAND    *pCand = NULL;
    int         cnBits, bAtomRadRemoved = 0;

    int num_at = pStruct->num_atoms;
    int num_deleted_H = pStruct->num_deleted_H;
    int len_at = num_at + num_deleted_H;

    for (i = pBNS->num_atoms, num_rad_not_atom = 0; i < pBNS->num_vertices; i++)
    {
        num_rad_not_atom += pBNS->vert[i].st_edge.cap - pBNS->vert[i].st_edge.flow;
    }
    if (!num_rad_not_atom)
    {
        goto exit_function;
    }
    /****************************************************/
    /*                                                  */
    /*    Move radicals from ChargeStruct to atoms      */
    /*                                                  */
    /****************************************************/

    /* allocate memory to keep track of moved radicals */
    pnRad = (S_SHORT *) inchi_malloc( pBNS->num_vertices * sizeof( pnRad[0] ) );
    pnDelta = (S_SHORT *) inchi_calloc( pBNS->num_atoms, sizeof( pnDelta[0] ) );
    if (!pnRad || !pnDelta)
    {
        ret = RI_ERR_ALLOC;
        goto exit_function;
    }
    for (i = 0; i < pBNS->num_vertices; i++)
    {
        pnRad[i] = pBNS->vert[i].st_edge.cap - pBNS->vert[i].st_edge.flow;
    }
    while (1)
    {
        /* remove radicals from atoms */
        for (i = 0; i < pBNS->num_atoms; i++)
        {
            pnDelta[i] = pBNS->vert[i].st_edge.cap - pBNS->vert[i].st_edge.flow;
            pBNS->vert[i].st_edge.cap -= pnDelta[i];
            bAtomRadRemoved += ( 0 != pnDelta[i] );
        }
        ret = SetRadEndpoints( pBNS, pBD, RAD_SRCH_FROM_FICT );
        if (!ret)
        {
            break;
        }
        if (ret < 0)
        {
            goto exit_function;
        }
        nNumRad = ret;
        for (i = 0; i < nNumRad; i++)
        {
            pEdge = pBNS->edge + pBD->RadEdges[i];
            v1 = pEdge->neighbor1;
            v2 = pEdge->neighbor12 ^ v1;
            pBNS->vert[v1].st_edge.flow -= pEdge->flow;
            pBNS->vert[v2].st_edge.flow -= pEdge->flow;
            pBNS->tot_st_flow -= 2 * pEdge->flow;
            pEdge->flow = 0;
            pEdge->forbidden |= forbidden_mask;
            pBNS->edge_forbidden_mask |= forbidden_mask;
        }
        ret = RunBnsRestoreOnce( pBNS, pBD, pVA, pTCGroups );
        if (ret < 0)
        {
            goto exit_function;
        }
        else
        {
            num_moved += ret;
        }
        RemoveRadEndpoints( pBNS, pBD, NULL );
        if (ret == 0)
        {
            break;  /* could not move more radicals */
        }
        if (bAtomRadRemoved)
        {
            /* restore radicals to atoms */
            for (i = 0; i < pBNS->num_atoms; i++)
            {
                pBNS->vert[i].st_edge.cap += pnDelta[i];
            }
            bAtomRadRemoved = 0;
        }
    }
    if (bAtomRadRemoved)
    {
        /* restore radicals to atoms */
        for (i = 0; i < pBNS->num_atoms; i++)
        {
            pBNS->vert[i].st_edge.cap += pnDelta[i];
        }
        /* djb-rwth: removing redundant code */
    }
    pBNS->edge_forbidden_mask &= ~forbidden_mask;


    /****************************************************/
    /*                                                  */
    /*    Fix the charges                               */
    /*                                                  */
    /****************************************************/
    if (num_moved)
    {
        /* find reqired charge */
        extra_charge = 0;
        for (i = pBNS->num_atoms, pv = pBNS->vert + i; i < pBNS->num_vertices; i++, pv++)
        {
            if ((delta = pv->st_edge.cap - pv->st_edge.flow)) /* djb-rwth: addressing LLVM warning */
            {
                if (IS_BNS_VT_C_OR_CSUPER_GR( pv->type ))
                {
                    extra_charge -= delta;
                }
                else
                    if (BNS_VERT_TYPE__AUX == pv->type)
                    {
                        extra_charge += delta;
                    }
                    else
                    {
                        ret = RI_ERR_PROGR;
                        goto exit_function;
                    }
            }
        }
        if (!extra_charge)
        {
            goto exit_function;
        }
        /* find differences */
        num_candidates = 0;
        for (i = 0; i < pBNS->num_vertices; i++)
        {
            pnRad[i] = ( pBNS->vert[i].st_edge.cap - pBNS->vert[i].st_edge.flow ); /* djb-rwth: garbage values on the right side of - -- discussion required; pnRad[i] = ( pBNS->vert[i].st_edge.cap - pBNS->vert[i].st_edge.flow ) - pnRad[i]; */
            if (pnRad[i] > 0 && i < pBNS->num_atoms && !pVA[i].nTautGroupEdge)
            {
                num_candidates++;
            }
        }
    }
    if (num_candidates > 0)
    {
        pCand = (CC_CAND *) inchi_calloc( num_candidates, sizeof( pCand[0] ) );
        if (!pCand)
        {
            ret = RI_ERR_ALLOC;
            goto exit_function;
        }
        /* create atom */
        memcpy(at2, at, len_at * sizeof(at2[0]));
        pStruct->at = at2;
        ret2 = CopyBnsToAtom( pStruct, pBNS, pVA, pTCGroups, 1 );
        pStruct->at = at;
        if (ret2 < 0)
        {
            ret = ret2;
            goto exit_function;
        }

        for (i = 0, j = 0; i < pBNS->num_vertices; i++)
        {
            if (pnRad[i] > 0 && i < pBNS->num_atoms && !pVA[i].nTautGroupEdge) /* djb-rwth: ignoring LLVM warning as pnRad is initialised above */
            {
                pCand[j].iat = i;
                pCand[j].num_bonds = at2[i].valence;
                pCand[j].chem_valence = at2[i].chem_bonds_valence;
                pCand[j].cMetal = pVA[i].cMetal;
                pCand[j].cNumBondsToMetal = pVA[i].cNumBondsToMetal;
                pCand[j].cNumValenceElectrons = pVA[i].cNumValenceElectrons;
                pCand[j].cPeriodicRowNumber = pVA[i].cPeriodicRowNumber;
                pCand[j].el_number = at2[i].el_number;
                cnBits = ( pVA[i].cnListIndex > 0 ) ? cnList[pVA[i].cnListIndex - 1].bits : 0;
                while (cnBits > 0)
                {
                    pCand[j].cNumChargeStates++;
                    cnBits >>= cn_bits_shift;
                }
                j++;
            }
        }
        if (j > 1)
        {
            qsort( pCand, j, sizeof( pCand[0] ), comp_cc_cand );
        }
        added_charge = 0;

        for (k = 0; k < j; k++)
        {
            int rest_of_charge = extra_charge - added_charge;
            int charge_per_left_atom = ( abs( rest_of_charge ) + j - k - 1 ) / ( j - k );
            int this_atom_add_charge = rest_of_charge > 0 ? charge_per_left_atom : -charge_per_left_atom;
            pVA[pCand[k].iat].cInitCharge += this_atom_add_charge;
            added_charge += this_atom_add_charge;
            if (this_atom_add_charge)
            {
                for (i = pBNS->num_vertices - 1, pv = pBNS->vert + i; this_atom_add_charge && pBNS->num_atoms <= i; i--, pv--)
                {
                    if ((delta = pv->st_edge.cap - pv->st_edge.flow)) /* djb-rwth: addressing LLVM warning */
                    {
                        if (this_atom_add_charge < 0 && IS_BNS_VT_C_OR_CSUPER_GR( pv->type ))
                        {
                            if (delta + this_atom_add_charge > 0)
                            {
                                delta = -this_atom_add_charge;
                            }
                            pv->st_edge.cap -= delta;
                            pBNS->tot_st_cap -= delta;
                            this_atom_add_charge += delta;
                        }
                        else
                        {
                            if (this_atom_add_charge > 0 && BNS_VERT_TYPE__AUX == pv->type)
                            {
                                if (delta > this_atom_add_charge)
                                {
                                    delta = this_atom_add_charge;
                                }
                                pv->st_edge.cap -= delta;
                                pBNS->tot_st_cap -= delta;
                                this_atom_add_charge -= delta;
                            }
                        }
                    }
                }
            }
        }
    }

exit_function:
    if (pnRad)
    {
        inchi_free( pnRad );
    }
    if (pnDelta)
    {
        inchi_free( pnDelta );
    }
    if (pCand)
    {
        inchi_free( pCand );
    }

    return ret;
}


#endif


/****************************************************************************/
typedef struct tagMobileHGroups {
    AT_NUMB group_number;
    AT_NUMB atom_number;
    AT_NUMB atom_type_pVA;
    S_CHAR  ineigh;
    S_CHAR  bond_type;
    S_CHAR  forbidden;
   /* S_CHAR  el_type;*/
    S_CHAR  endpoint_valence;
    S_CHAR  num_bonds;
    S_CHAR  bonds_valence;
    S_CHAR  num_bonds_non_metal;
    S_CHAR  bonds_valence_non_metal;
} MOBILE_GR;

typedef struct tagMobileGroupList {
    AT_NUMB group_number;
    AT_NUMB num;
} MGROUPS;
/****************************************************************************/


/****************************************************************************/
int AdjustTgroupsToForbiddenEdges2( BN_STRUCT *pBNS,
                                    inp_ATOM *at,
                                    VAL_AT *pVA,
                                    int num_atoms,
                                    int forbidden_mask )
{
    int i, j, k;
    int centerpoint_type, neigh_type;
    int num_changes;
    int num_donors, num_acceptors, num_donor_endpoints, num_acceptor_endpoints;
    int neigh, tg_number, num_eql_mobile_gr, num_dif_mobile_gr, bond_type, has_mobile_H; /* djb-rwth: removing redundant variables */
    int num_forbidden, ind_forbidden, forbidden, num_N, num_O, num_P, num_S, num_OSt;
    int val, delta_val, delta_met, num_bonds_non_metal, bonds_valence_non_metal;
    /* djb-rwth: removing redundant variables */
    int inv_forbidden_mask = ~forbidden_mask;
    MOBILE_GR MobileGr[MAXVAL];
    int       num_endpoints;
    MGROUPS   MGroups[MAXVAL];
    int       num_mgroups, num_diff_t_groups;
    BNS_EDGE   *e, *e1, *e2, *ev, *ev1, *ev2;
    BNS_VERTEX *pv1, *pv2;
    num_changes = 0;
    /* search for possible centerpoints */
    for (i = 0; i < num_atoms; i++)
    {

        if (at[i].chem_bonds_valence == at[i].valence || at[i].num_H ||
             at[i].endpoint || at[i].charge || at[i].radical ||
             !is_centerpoint_elem( at[i].el_number ) ||
             !( centerpoint_type = get_pVA_atom_type( pVA, at, i, 0 ) ) ||
             2 > ( delta_val = at[i].chem_bonds_valence - ( val = get_el_valence( at[i].el_number, 0, 0 ) ) ) ||
             2 > ( delta_met = ( bonds_valence_non_metal = nNoMetalBondsValence( at, i ) ) - val )
           ) /* djb-rwth: ignoring LLVM warning: variable used to store function return value */
        {
            continue;
        }

        num_donors = num_acceptors = num_donor_endpoints = num_acceptor_endpoints = 0;
        num_mgroups = num_endpoints = num_diff_t_groups = 0;
        has_mobile_H = num_eql_mobile_gr = num_dif_mobile_gr = tg_number = 0; /* djb-rwth: removing redundant code */
        ind_forbidden = -1;
        num_forbidden = 0;
        num_N = num_O = num_P = num_S = num_OSt = 0;
        num_bonds_non_metal = nNoMetalNumBonds( at, i );
        /* djb-rwth: removing redundant code */
        /* djb-rwth: removing redundant code */

        for (j = 0; j < at[i].valence; j++)
        {
            /* collect neighbors info */
            neigh = at[i].neighbor[j];
            val = get_endpoint_valence( at[neigh].el_number );
            forbidden = pBNS->edge[(int) pBNS->vert[i].iedge[j]].forbidden;
            bond_type = ( at[i].bond_type[j] & BOND_TYPE_MASK );
            neigh_type = get_pVA_atom_type( pVA, at, neigh, bond_type );
            if (!forbidden && !at[neigh].endpoint)
            {
                /* save forbidden bonds */
                if (is_el_a_metal( at[neigh].el_number ))
                {
                    continue;
                }
                switch (bond_type)
                {
                    case BOND_TYPE_SINGLE:
                        if (!at[neigh].num_H && at[neigh].charge != -1)
                        {
                            continue; /* not a donor */
                        }
                        break;
                    case BOND_TYPE_DOUBLE:
                        if (!neigh_type)
                        {
                            continue;
                        }
                        break;
                    default:
                        continue;
                }
            }

            MobileGr[num_endpoints].atom_number = neigh;
            MobileGr[num_endpoints].ineigh = j;
            MobileGr[num_endpoints].bond_type = bond_type;
            MobileGr[num_endpoints].group_number = at[neigh].endpoint;
            MobileGr[num_endpoints].endpoint_valence = val;
            MobileGr[num_endpoints].forbidden = forbidden;
            MobileGr[num_endpoints].atom_type_pVA = neigh_type;
            MobileGr[num_endpoints].num_bonds = at[neigh].valence;
            MobileGr[num_endpoints].bonds_valence = at[neigh].chem_bonds_valence;
            MobileGr[num_endpoints].num_bonds_non_metal = nNoMetalNumBonds( at, neigh );
            MobileGr[num_endpoints].bonds_valence_non_metal = nNoMetalBondsValence( at, neigh );

            if (forbidden & forbidden_mask)
            {
                num_forbidden++;
                ind_forbidden = num_endpoints;
            }
            num_O += 0 != ( neigh_type & EL_TYPE_O ) && at[neigh].valence == 1; /* ignore -O- */
            num_N += 0 != ( neigh_type & EL_TYPE_N ) &&
                !( at[neigh].valence == 3 && at[neigh].chem_bonds_valence == 3 ); /* ignore -N< */
            num_S += 0 != ( neigh_type & EL_TYPE_S ) && at[neigh].valence == 1; /* ignore -S- */
            num_P += 0 != ( neigh_type & EL_TYPE_P ) &&
                !( at[neigh].valence == 3 && at[neigh].chem_bonds_valence == 3 ); /* ignore -P< */
            num_OSt += 0 != ( neigh_type & EL_TYPE_OSt );
            num_acceptors += ( bond_type == BOND_TYPE_DOUBLE ) && ( neigh_type & EL_TYPE_PT );
            num_donors += ( bond_type == BOND_TYPE_SINGLE ) && ( neigh_type & EL_TYPE_PT ) &&
                ( at[neigh].num_H || at[neigh].charge == -1 || at[neigh].endpoint );
            if (at[neigh].endpoint)
            {
                num_acceptor_endpoints += ( bond_type == BOND_TYPE_DOUBLE );
                num_donor_endpoints += ( bond_type == BOND_TYPE_SINGLE );
                if (!tg_number)
                {
                    tg_number = at[neigh].endpoint;
                    num_eql_mobile_gr = 1;
                }
                else
                {
                    if (tg_number == at[neigh].endpoint)
                    {
                        num_eql_mobile_gr++;
                    }
                    else
                    {
                        num_dif_mobile_gr++;
                    }
                }
            }
            else
            {
                if (bond_type == BOND_TYPE_SINGLE && val)
                {
                    if (at[neigh].endpoint)
                    {
                        has_mobile_H |= 1;
                        /* djb-rwth: removing redundant code */
                    }
                    else
                    {
                        has_mobile_H |= ( 0 != at[neigh].num_H );
                        /* djb-rwth: removing redundant code */
                    }
                }
            }
            num_endpoints++;

            if (at[neigh].endpoint || ( neigh_type & EL_TYPE_PT ))
            {
                for (k = 0; k < num_mgroups; k++)
                {
                    if (MGroups[k].group_number == at[neigh].endpoint)
                    {
                        MGroups[k].num++;
                        break;
                    }
                }
                if (k == num_mgroups)
                {
                    MGroups[k].group_number = at[neigh].endpoint;
                    MGroups[k].num = 1;
                    num_mgroups++;
                    num_diff_t_groups += ( 0 != at[neigh].endpoint );
                }
            }
        }
        if (!num_acceptors || !num_donors || /* num_acceptors > 2 ||*/
             (num_eql_mobile_gr == num_endpoints && !num_forbidden) ||
             (!tg_number && !has_mobile_H)) /* djb-rwth: addressing LLVM warnings */
        {
            continue; /* nothing to do */
        }

        /* case_5_1: */
        /***************** determine the case ************************/
        if (3 == num_bonds_non_metal &&
             4 == bonds_valence_non_metal &&
             ( centerpoint_type == EL_TYPE_C ) &&
             2 == num_O && 1 == num_N + num_S && num_OSt &&
             1 == num_forbidden && 3 == num_eql_mobile_gr)
        {
            /********************************************************
             ***         InChI Tech. Man., Table 5, case 1        ***
             ********************************************************
                       2
                      OH                OH     X  =  N, S, Se, Te
                     /                 /       f  =  fixed bond
                 e  /                 /        tg =  Mobile-H vertex
              HX---C      -->    X===C
            ev2|| f  \\ ev1         f  \
               ||     \\                \
               tg------O                 OH
                        1
             Problem:
               XH, O, and O belong to the same Mobile-H group.
               Fixed bond prevents the correct structure restoration:
               H cannot migrate from X to O because HX-N bond is fixed
             Solution:
               Move H from X to allow XH-C bond change
               (this unfixes the bond, see SetForbiddenEdges(...) )
             *********************************************************/
            int jXH = -1, jO1 = -1, jO2 = -1, n = 0;
            for (j = 0; j < num_endpoints; j++)
            {
                if (( MobileGr[j].atom_type_pVA & ( EL_TYPE_N | EL_TYPE_S ) ) &&
                    ( MobileGr[j].forbidden == forbidden_mask ) &&
                     MobileGr[j].bond_type == BOND_TYPE_SINGLE &&
                     jXH < 0)
                {
                    jXH = j;
                    n++;
                }
                else
                {
                    if (( MobileGr[j].atom_type_pVA & EL_TYPE_MASK ) == EL_TYPE_O &&
                            MobileGr[j].num_bonds_non_metal == 1 &&
                            !MobileGr[j].forbidden)
                    {
                        if (MobileGr[j].bond_type == BOND_TYPE_DOUBLE && jO1 < 0)
                        {
                            jO1 = j;
                            n++;
                        }
                        else
                        {
                            if (MobileGr[j].bond_type == BOND_TYPE_SINGLE && jO2 < 0)
                            {
                                jO2 = j;
                                n++;
                            }
                        }
                    }
                }
            }
            if (n != 3)
            {
                goto case_5_2;
            }
            /* XH-C edge */
            e = pBNS->edge + pBNS->vert[i].iedge[MobileGr[jXH].ineigh];
            /* C=O  edge */
            ev1 = pBNS->edge + pBNS->vert[i].iedge[MobileGr[jO1].ineigh];
            /* XH-tg edge */
            ev2 = pBNS->edge + pVA[MobileGr[jXH].atom_number].nTautGroupEdge - 1;

            if (!ev1->flow || !ev2->flow)
            {
                goto case_5_2;
            }

            /* do not remove forbidden edge bit */
            e->flow++;
            ev1->flow--;
            ev2->flow--;
            pBNS->vert[ev1->neighbor12 ^ i].st_edge.flow--;
            pBNS->vert[ev2->neighbor12 ^ ev2->neighbor1].st_edge.flow--;
            pBNS->tot_st_flow -= 2;
            num_changes++;
            continue;
        }
    case_5_2:
            /*********************************************************************/
        if (3 == num_bonds_non_metal &&
             5 == bonds_valence_non_metal &&
             ( centerpoint_type == EL_TYPE_N ) &&
             2 == num_O && 1 == num_N + num_S &&
             1 == num_forbidden && 3 == num_eql_mobile_gr)
        {
            /********************************************************
             ***         InChI Tech. Man., Table 5, case 2        ***
             ********************************************************

                      O                 OH     X  =  N, S, Se, Te
                     //                /       f  =  fixed bond
                 e  //                /        tg =  Mobile-H vertex
              HX---N      -->    X===N
            ev2|| f  \\ ev1         f  \\
               ||     \\                \\
               tg------O                 O

             Problem:
               XH, O, and O belong to the same Mobile-H group.
               Fixed bond prevents the correct structure restoration:
               H cannot migrate from X to O because HX-N bond is fixed
             Solution:
               Move H from X to allow XH-N bond change
               (this unfixes the bond, see SetForbiddenEdges(...) )
             *********************************************************/
            int jXH = -1, jO1 = -1, jO2 = -1, n = 0;
            for (j = 0; j < num_endpoints; j++)
            {
                if (( MobileGr[j].atom_type_pVA & ( EL_TYPE_N | EL_TYPE_S ) ) &&
                    ( MobileGr[j].forbidden == forbidden_mask ) &&
                     MobileGr[j].bond_type == BOND_TYPE_SINGLE &&
                     jXH < 0)
                {
                    jXH = j;
                    n++;
                }
                else
                {
                    if (( MobileGr[j].atom_type_pVA & EL_TYPE_MASK ) == EL_TYPE_O &&
                            MobileGr[j].bond_type == BOND_TYPE_DOUBLE &&
                            MobileGr[j].num_bonds_non_metal == 1 &&
                            !MobileGr[j].forbidden)
                    {
                        if (jO1 < 0)
                        {
                            jO1 = j;
                            n++;
                        }
                        else
                        {
                            if (jO2 < 0)
                            {
                                jO2 = j;
                                n++;
                            }
                        }
                    }
                }
            }
            if (n != 3)
            {
                goto case_5_4;
            }
            /* XH-N edge */
            e = pBNS->edge + pBNS->vert[i].iedge[MobileGr[jXH].ineigh];
            /* N=O  edge */
            ev1 = pBNS->edge + pBNS->vert[i].iedge[MobileGr[jO1].ineigh];
            /* XH-tg edge */
            ev2 = pBNS->edge + pVA[MobileGr[jXH].atom_number].nTautGroupEdge - 1;

            if (!ev1->flow || !ev2->flow)
            {
                goto case_5_4;
            }
            /* do not remove forbidden edge bit */
            e->flow++;
            ev1->flow--;
            ev2->flow--;
            pBNS->vert[ev1->neighbor12 ^ i].st_edge.flow--; /* first =O vertex */
            pBNS->vert[ev2->neighbor12 ^ ev2->neighbor1].st_edge.flow--; /* taut group vertex tg */
            pBNS->tot_st_flow -= 2;
            num_changes++;
            continue;
        }

    case_5_4:
            /*********************************************************************/
        if (3 == num_bonds_non_metal &&
             5 == bonds_valence_non_metal &&
             ( centerpoint_type & ( EL_TYPE_N | EL_TYPE_P ) ) &&
             1 == num_O + num_S && 0 < num_N && 2 == ( num_N + num_P ) &&
             1 == num_forbidden && num_O + num_S + num_N == num_eql_mobile_gr)
        {
            /********************************************************
             ***         InChI Tech. Man., Table 5, case 4        ***
             ********************************************************
                                               O  =  O, S, Se, Te
                       X                 X     X  =  N, P, As
                     //                //      f  =  fixed bond
                 e  // ev2            //       tg =  Mobile-H vertex
               O===N      -->   HO---N
              || f  \  ev1         f  \\
              ||     \                 \\
              tg------NH                N

            Problem:
              O, NH, and possibly X belong to the same Mobile-H group.
              Fixed bond prevents the correct structure restoration:
              H cannot migrate from NH to O because O=N bond is fixed
            Solution:
              Move H from NH to O to allow O=N bond change
              (this unfixes the bond, see fix_special_bonds(...) )
            *********************************************************/
            int jO = -1, jNH = -1, jX = -1, n = 0;
            for (j = 0; j < num_endpoints; j++)
            {
                if (( MobileGr[j].atom_type_pVA & ( EL_TYPE_O | EL_TYPE_S ) ) &&
                     MobileGr[j].forbidden == forbidden_mask &&
                     MobileGr[j].bond_type == BOND_TYPE_DOUBLE &&
                     MobileGr[j].num_bonds_non_metal == 1 &&
                     jO < 0)
                {
                    jO = j;
                    n++;
                }
                else
                {
                    if (( MobileGr[j].atom_type_pVA & ( EL_TYPE_N | EL_TYPE_P ) ) &&
                            !MobileGr[j].forbidden)
                    {
                        if (MobileGr[j].bond_type == BOND_TYPE_SINGLE &&
                            ( MobileGr[j].atom_type_pVA & EL_TYPE_MASK ) == EL_TYPE_N && jNH < 0)
                        {
                            jNH = j;
                            n++;
                        }
                        else
                        {
                            if (MobileGr[j].bond_type == BOND_TYPE_DOUBLE && jX < 0)
                            {
                                jX = j;
                                n++;
                            }
                        }
                    }
                }
            }
            if (n != 3)
            {
                goto case_5_6;
            }
            /* O=N edge */
            e = pBNS->edge + pBNS->vert[i].iedge[MobileGr[jO].ineigh];
            /* N-NH  edge */
            ev1 = pBNS->edge + pBNS->vert[i].iedge[MobileGr[jNH].ineigh];
            /* N=X edge */
            ev2 = pBNS->edge + pBNS->vert[i].iedge[MobileGr[jX].ineigh];

            if (!e->flow)
            {
                goto case_5_6;
            }
            /* do not remove forbidden edge bit */
            e->flow--;
            ev1->flow++;
            pBNS->vert[e->neighbor12 ^ i].st_edge.flow--;
            pBNS->vert[ev1->neighbor12 ^ i].st_edge.flow--;
            pBNS->tot_st_flow -= 2;
            num_changes++;
            continue;
        }
    case_5_6:
            /********* InChI Tech.Man. Table 5, case 6 **************/
        if (2 == delta_met && 4 == num_bonds_non_metal &&
             5 == bonds_valence_non_metal &&
             1 == num_forbidden && 1 < num_eql_mobile_gr &&
             !num_dif_mobile_gr &&
             ( centerpoint_type & ( EL_TYPE_N | EL_TYPE_P ) ) &&
             1 <= num_N && 2 <= num_N + num_O + num_S &&
             1 == num_acceptor_endpoints && 0 < num_donor_endpoints)
        {
            int jN = -1, njFix = 0, jFix[4], n = 0;
            /* centerpoint is N, P, As, Sb

                input             output
                -----             ------
                    end
                    po-
                    int
                    2

                X  ZH              X  Z     Z=N,O,S,Se,Te [terminal endpoint]
                \ |                \ ||
                \| f   f           \||
                Y---N===N---       Y---N---NH---
                    e                  f
                cen  end         no bond
                ter  po-         fixed
                po-  int
                int  1        tautomerism O==N--NH is allowed

                Problem: OH and =N- belong to a Mobile-H group, but
                        forbidden edge e does not allow them to be
                        tautomeric in the restored structure.

                Solution:

                1. Decrement flow in edge e
                2. Decrement st_edge flow in N and N connected by e
                3. Fix all single order bonds to not terminal tautomeric N around N(centerpoint)
                4. Run BNS to establist new flow distribution
            */

            /* fixed bond */
            for (j = 0; j < num_endpoints; j++)
            {
                neigh = MobileGr[j].atom_number;
                if (MobileGr[j].bond_type == BOND_TYPE_DOUBLE &&
                    ( MobileGr[j].atom_type_pVA & EL_TYPE_MASK ) == EL_TYPE_N &&
                     MobileGr[j].num_bonds_non_metal == 2 &&
                     MobileGr[j].bonds_valence_non_metal == 3 &&
                     at[neigh].endpoint &&
                     !at[neigh].num_H && !at[neigh].charge &&
                     !at[neigh].radical &&
                     ( MobileGr[j].forbidden & forbidden_mask ) && jN < 0)
                {
                    jN = j;
                    n++;
                }
                else
                {
                    if (MobileGr[j].bond_type == BOND_TYPE_SINGLE &&
                            at[neigh].endpoint)
                    {
                        if (MobileGr[j].num_bonds > 1)
                        {
                            jFix[njFix++] = j;
                        }
                        n++;
                    }
                }
            }

            if (jN < 0 || n < 2 || 1 + njFix == n)
            {
                goto case_5_7;  /* nothing to do */
            }

            e = pBNS->edge + pBNS->vert[i].iedge[MobileGr[jN].ineigh];  /* fixed edge */
            if (!e->flow)
            {
                goto case_5_7;
            }
            e->flow--;
            pBNS->vert[i].st_edge.flow--;
            pBNS->vert[e->neighbor12 ^ i].st_edge.flow--;
            pBNS->tot_st_flow -= 2;

            for (j = 0; j < njFix; j++)
            {
/* edges to fix */
                ev = pBNS->edge + pBNS->vert[i].iedge[(int) MobileGr[jFix[j]].ineigh];
                ev->forbidden |= forbidden_mask;
            }
            num_changes++;
            continue;
        }
    case_5_7:
            /*********************************************************************/
        if (3 == num_bonds_non_metal &&
             4 == bonds_valence_non_metal &&
             ( centerpoint_type == EL_TYPE_S ) &&
             2 == num_O + num_S && 1 == num_OSt && 1 == num_N &&
             1 == num_forbidden && 3 == num_eql_mobile_gr &&
             MobileGr[ind_forbidden].bond_type == BOND_TYPE_SINGLE)
        {
            /********************************************************
             ***         InChI Tech. Man., Table 5, case 7        ***
             ********************************************************
                                               O  =  O, S, Se, Te
                      OH                OH     S  =  S, Se, Te
                     /                 /       f  =  fixed bond
                 e  /ev2           f  /        tg =  Mobile-H vertex
              HN---S      -->    N===S         X  =  N or non-endpoint;
              || f  \\                \
            ev2||     \\ev1             \
               tg------O                 OH
                                                N, O, O
             Problem:                           =======
               O, NH, OH belong to the same Mobile-H group.
               Fixed bond prevents the correct structure restoration:
               H cannot migrate from NH to O because HN-S bond is fixed
             Solution:
               Move H from NH to =O to allow HN=S bond change by making a 2nd terminal -OH
               (this unfixes the bond, see fix_special_bonds(...) )
             *********************************************************/
            int jO = -1, jNH = -1, jOH = -1, n = 0;
            for (j = 0; j < num_endpoints; j++)
            {
                if (( MobileGr[j].atom_type_pVA & EL_TYPE_MASK ) == EL_TYPE_N &&
                     MobileGr[j].forbidden == forbidden_mask &&
                     MobileGr[j].bond_type == BOND_TYPE_SINGLE &&
                     MobileGr[j].num_bonds_non_metal <= 2 &&
                     jNH < 0)
                {
                    jNH = j;
                    n++;
                }
                else
                {
                    if (( MobileGr[j].atom_type_pVA & ( EL_TYPE_O | EL_TYPE_S ) ) &&
                            !MobileGr[j].forbidden &&
                            MobileGr[j].num_bonds_non_metal == 1)
                    {
                        if (MobileGr[j].bond_type == BOND_TYPE_DOUBLE &&
                             jO < 0)
                        {
                            jO = j;
                            n++;
                        }
                        else
                        {
                            if (jOH < 0)
                            {
                                jOH = j;
                                n++;
                            }
                        }
                    }
                }
            }
            if (n != 3)
            {
                goto case_5_9a;
            }
            /* NH-S edge */
            e = pBNS->edge + pBNS->vert[i].iedge[MobileGr[jNH].ineigh];
            /* S=O  edge */
            ev1 = pBNS->edge + pBNS->vert[i].iedge[MobileGr[jO].ineigh];
            /* XH-tg edge */
            ev2 = pBNS->edge + pVA[MobileGr[jNH].atom_number].nTautGroupEdge - 1;

            if (!ev1->flow || !ev2->flow)
            {
                goto case_5_9a;
            }

            /* do not remove forbidden edge bit */
            e->flow++;
            ev1->flow--;
            ev2->flow--;
            pBNS->vert[ev1->neighbor12 ^ i].st_edge.flow--; /* first =O vertex */
            pBNS->vert[ev2->neighbor12 ^ ev2->neighbor1].st_edge.flow--; /* taut group vertex tg */
            pBNS->tot_st_flow -= 2;
            num_changes++;
            continue;
        }
    case_5_9a:
            /*********************************************************************/
        if (3 == num_bonds_non_metal &&
             4 == bonds_valence_non_metal &&
             ( centerpoint_type == EL_TYPE_S ) &&
             1 == num_O + num_S && !num_OSt && 1 <= num_N &&
             1 == num_forbidden &&
             num_O + num_S + num_N == num_eql_mobile_gr &&
             MobileGr[ind_forbidden].bond_type == BOND_TYPE_SINGLE)
        {
            /********************************************************
             ***         InChI Tech. Man., Table 5, case 9a       ***
             ********************************************************
                                               O  =  O, S, Se, Te
                      X                 X      S  =  S, Se, Te
                     /                 /       f  =  fixed bond
                    /                 /        tg =  Mobile-H vertex
              HN---S      -->    N===S         X  =  N or non-endpoint;
              ||    \\ e              \       -X is not -O(terminal)
              ||    f\\               f\
              tg------O                 OH
                                               N, N, O  or N, O
            Problem:                           ================
              O, NH belong to the same Mobile-H group.
              Fixed bond prevents the correct structure restoration:
              H cannot migrate from NH to O because O=S bond is fixed
            Solution:
              Move H from NH to =O to allow O=S bond change by making a terminal -OH
              (this unfixes the bond, see fix_special_bonds(...) )
            *********************************************************/
            int jO = -1, jNH = -1, jX = -1, n = 0; /* djb-rwth: ignoring LLVM warning: variable used */
            for (j = 0; j < num_endpoints; j++)
            {
                if (( MobileGr[j].atom_type_pVA & ( EL_TYPE_O | EL_TYPE_S ) ) &&
                     MobileGr[j].forbidden == forbidden_mask &&
                     MobileGr[j].bond_type == BOND_TYPE_DOUBLE &&
                     MobileGr[j].num_bonds_non_metal == 1 &&
                     jO < 0)
                {
                    jO = j;
                    n++;
                }
                else
                {
                    if (( MobileGr[j].atom_type_pVA & EL_TYPE_MASK ) == EL_TYPE_N &&
                            !MobileGr[j].forbidden &&
                            MobileGr[j].bond_type == BOND_TYPE_SINGLE &&
                            jNH < 0)
                    {
                        jNH = j;
                        n++;
                    }
                    else
                    {
                        if (jX < 0)
                        {
                            jX = j;
                            n++;
                        }
                    }
                }
            }
            if (jO < 0 || jNH < 0)
            {
                goto case_5_8b_to_9b;
            }

            e = pBNS->edge + pBNS->vert[i].iedge[MobileGr[ind_forbidden].ineigh];
            if (!e->flow)
            {
                goto case_5_8b_to_9b;
            }
            e->flow--;
            pBNS->vert[e->neighbor1].st_edge.flow--;
            pBNS->vert[e->neighbor1 ^ e->neighbor12].st_edge.flow--;
            pBNS->tot_st_flow -= 2;
            num_changes++;
            continue;
        }
    case_5_8b_to_9b: /* #1 */
            /*********************************************************************/
        if (3 == num_bonds_non_metal &&
             4 == bonds_valence_non_metal &&
             ( centerpoint_type == EL_TYPE_S ) &&
             0 == num_O + num_S && 2 == num_N && 0 == num_P && !num_OSt &&
             1 == num_forbidden &&
             1 == num_eql_mobile_gr && 0 == num_dif_mobile_gr &&
             1 == num_donor_endpoints && 0 == num_acceptor_endpoints &&
             1 == num_donors && 1 == num_acceptors &&
             MobileGr[ind_forbidden].bond_type == BOND_TYPE_SINGLE)
        {
            /********************************************************
             ***         InChI Tech. Man., Table 5, case 8b->9b   ***
             ********************************************************
                             --->                    O  =  O, S, Se, Te
                      X                  X           S  =  S, Se, Te
             \      f/          \      f/            f  =  fixed bond
              \ ev  /  C=====Z   \     /  C-----ZH   tg =  Mobile-H vertex
               N===S   |     |    N===S  ||     ||   X  =  is N not an endpoint;
             not    \  |     |         \ ||     ||  -X is not terminal -O,-S,-Se,-Te or
             an      \ |  e  |          \||  e  ||        any N, P, As
            endpoint   NH=====tg          N------tg
                      is an                   f       N, N, X, fixed single
                    endpoint                          =====================

             Problem:
               N is not a Mobile-H endpoint, NH is a Mobile-H endpoint
               Unfixed bond N==S prevents the correct structure restoration:
               H can migrate from NH to N because N=S bond is not fixed
             Solution:
               Move H from NH to =Z to make N=S bond fixed (Table 5, case 9)
               (this unfixes the bond, see fix_special_bonds(...) )
             *********************************************************/
            int jN = -1, jNH = -1, jX = -1, n = 0;
            for (j = 0; j < num_endpoints; j++)
            {
                if (( MobileGr[j].atom_type_pVA & EL_TYPE_MASK ) == EL_TYPE_N &&
                     !( MobileGr[j].forbidden & forbidden_mask ))
                {
                    if (MobileGr[j].bond_type == BOND_TYPE_DOUBLE &&
                         !at[MobileGr[j].atom_number].endpoint &&
                         jN < 0)
                    {
                        jN = j;
                        n++;
                    }
                    else
                    {
                        if (MobileGr[j].bond_type == BOND_TYPE_SINGLE &&
                              MobileGr[j].num_bonds == 2 &&
                              MobileGr[j].bonds_valence == 2 &&
                              at[MobileGr[j].atom_number].endpoint &&
                              jNH < 0)
                        {
                            jNH = j;
                            n++;
                        }
                    }
                }
                else
                {
                    if (!( ( MobileGr[j].atom_type_pVA & ( EL_TYPE_N | EL_TYPE_P ) ) ||
                        (( MobileGr[j].atom_type_pVA & ( EL_TYPE_O | EL_TYPE_S ) ) &&
                           MobileGr[j].num_bonds > 1 )) &&
                           ( MobileGr[j].forbidden & forbidden_mask ) &&
                            MobileGr[j].bond_type == BOND_TYPE_SINGLE &&
                            jX < 0) /* djb-rwth: addressing LLVM warning */
                    {
                        jX = j;
                        n++;
                    }
                }
            }
            if (n != 3)
            {
                goto case_5_8c_to_9c;
            }

            e = pBNS->edge + pVA[MobileGr[jNH].atom_number].nTautGroupEdge - 1;
            if (!e->flow)
            {
                goto case_5_8c_to_9c; /* should not happen ??? */
            }
            e->flow--;
            pBNS->vert[e->neighbor1].st_edge.flow--;
            pBNS->vert[e->neighbor1 ^ e->neighbor12].st_edge.flow--;
            pBNS->tot_st_flow -= 2;
            e->forbidden |= forbidden_mask;
            num_changes++;
            continue;
        }
    case_5_8c_to_9c: /* #2 */
            /*********************************************************************/
        if (3 == num_bonds_non_metal &&
             4 == bonds_valence_non_metal &&
             ( centerpoint_type == EL_TYPE_S ) &&
             0 == num_O + num_S && 3 == num_N && 0 == num_P &&
             1 == num_forbidden &&
             3 == num_eql_mobile_gr && 0 == num_dif_mobile_gr &&
             2 == num_donor_endpoints && 1 == num_acceptor_endpoints &&
             2 == num_donors && 1 == num_acceptors &&
             MobileGr[ind_forbidden].bond_type == BOND_TYPE_SINGLE)
        {
            /********************************************************
             ***         InChI Tech. Man., Table 5, case 8c->9c   ***
             ********************************************************
                is an endpoint --->                  O  =  O, S, Se, Te
                      NH2(X)             NH2(X)      S  =  S, Se, Te
             \       / pv1  pv2 \       /            f  =  fixed bond
              \ 1   /  C-----ZH  \     /  C=====Z    tg =  Mobile-H vertex
               N===S  ||     ||   N===S   |     |    X  =  is N not an endpoint;
            is an   \f||ev1  ||ev2     \f |     |   -X is not terminal -O,-S,-Se,-Te or
            endpoint   \||  e  ||         \ |  e  |         any N, P, As
                      2 N------tg          NH=====tg   C is a centerpoint of a t-group
                       is an                   f       N, N, X, fixed single
                     endpoint                          =====================

              Problem:
                N is not a Mobile-H endpoint, NH is a Mobile-H endpoint
                Unfixed bond N==S prevents the correct structure restoration:
                H can migrate from NH to N because N=S bond is not fixed
              Solution:
                Move H from NH to =Z to make N=S bond fixed (Table 5, case 9)
                (this unfixes the bond, see fix_special_bonds(...) )
              *********************************************************/
            int jN1 = -1, jN2 = -1, jX = -1, n = 0;
            EdgeIndex ie1, ie2; /* djb-rwth: removing redundant variables */
            for (j = 0; j < num_endpoints; j++)
            {
                if (( MobileGr[j].atom_type_pVA & EL_TYPE_MASK ) == EL_TYPE_N &&
                     !( MobileGr[j].forbidden & forbidden_mask ))
                {
                    if (MobileGr[j].bond_type == BOND_TYPE_DOUBLE &&
                         at[MobileGr[j].atom_number].endpoint &&
                         jN1 < 0)
                    {
                        jN1 = j;
                        n++;
                    }
                    else
                    {
                        if (MobileGr[j].bond_type == BOND_TYPE_SINGLE &&
                                MobileGr[j].num_bonds == 2 &&
                                MobileGr[j].bonds_valence == 3 &&
                                MobileGr[j].forbidden == forbidden_mask &&
                                at[MobileGr[j].atom_number].endpoint &&
                                jN2 < 0)
                        {
                            jN2 = j;
                            n++;
                        }
                        else
                        {
                            if (MobileGr[j].bond_type == BOND_TYPE_SINGLE &&
                                  MobileGr[j].num_bonds <= 2 &&
                                  MobileGr[j].bonds_valence <= 3 &&
                                  at[MobileGr[j].atom_number].endpoint &&
                                  jX < 0)
                            {
                                jX = j;
                                n++;
                            }
                        }
                    }
                }
            }
            if (n != 3)
            {
                goto case_5_9b_to_8b;
            }

            e = pBNS->edge + pVA[MobileGr[jN2].atom_number].nTautGroupEdge - 1;
            if (e->flow)
            {
                goto case_5_9b_to_8b; /* should not happen ??? */
            }
            pv1 = pBNS->vert + e->neighbor1;  /* must be jN2 */
            pv2 = pBNS->vert + ( e->neighbor1 ^ e->neighbor12 );
            /* djb-rwth: removing redundant code */
            ie1 = ie2 = -1;
            for (j = 0; j < pv1->num_adj_edges; j++)
            {
                ev1 = pBNS->edge + pv1->iedge[j];
                if (ev1->flow && !ev1->forbidden)
                {
                    ie1 = (int) ( ev1 - pBNS->edge );
                    pv1 = pBNS->vert + ( ev1->neighbor12 ^ ( pv1 - pBNS->vert ) );
                    break;
                }
            }
            for (j = 0; j < pv2->num_adj_edges; j++)
            {
                ev2 = pBNS->edge + pv2->iedge[j];
                if (ev2->flow && !ev2->forbidden)
                {
                    ie2 = (int) ( ev2 - pBNS->edge );
                    pv2 = pBNS->vert + ( ev2->neighbor12 ^ ( pv2 - pBNS->vert ) );
                    break;
                }
            }
            if (ie1 < 0 || ie2 < 0)
            {
                goto case_5_9b_to_8b;
            }
            e->flow++;
            e->forbidden |= forbidden_mask;
            ev1->flow--;
            ev2->flow--;
            pv1->st_edge.flow--;
            pv2->st_edge.flow--;
            pBNS->tot_st_flow -= 2;
            num_changes++;
            continue;
        }
    case_5_9b_to_8b: /* #3 */
            /*********************************************************************/
        if (3 == num_bonds_non_metal &&
             4 == bonds_valence_non_metal &&
             ( centerpoint_type == EL_TYPE_S ) &&
             0 == num_O + num_S && 2 == num_N && 0 == num_P &&
             1 == num_forbidden &&
             2 == num_eql_mobile_gr && 0 == num_dif_mobile_gr &&
             1 == num_donor_endpoints && 1 == num_acceptor_endpoints &&
             1 == num_donors && 1 == num_acceptors &&
             MobileGr[ind_forbidden].bond_type == BOND_TYPE_DOUBLE)
        {
            /********************************************************
                ***         InChI Tech. Man., Table 5, case 9b->8b   ***
                ********************************************************
                            --->                      O  =  O, S, Se, Te
                    X    is an              X          S  =  S, Se, Te
            \       /   endpoint    \       /           f  =  fixed bond
                \ 1ev /  C-----ZH       \     /  C=====Z   tg =  Mobile-H vertex
                N===S  ||     ||        N===S   |     |   X  =  is N not an endpoint;
            is an  f  \ ||     ||          f  \  |     |  -X is not terminal -O,-S,-Se,-Te or
            endpoint     2\||  e  ||              \ |  e  |        any N, P, As
                            N------tg               NH=====tg
                        is an                          f      N, N, X, fixed double
                        endpoint                                 =====================

                        Problem:
                        N1 and N2 are Mobile-H endpoints and belong to the same Mobile-H group.
                        Fixed bond N1==S prevents the correct structure restoration:
                        H cannot migrate ZH->N2->N1 because N1=S bond is fixed
                        Solution:
                        Move H from ZH to N2 to make N1=S bond unfixed and fix S-X bond (Table 5, case 8)
                        (see fix_special_bonds(...) for details )
                        *********************************************************/
            int jN1 = -1, jN2 = -1, jX = -1, n = 0; /* djb-rwth: ignoring LLVM warning: variable used */
            EdgeIndex ie1, ie2; /* djb-rwth: removing redundant variables */
            for (j = 0; j < num_endpoints; j++)
            {
                if (( MobileGr[j].atom_type_pVA & EL_TYPE_MASK ) == EL_TYPE_N)
                {
                    if (MobileGr[j].bond_type == BOND_TYPE_DOUBLE &&
                         at[MobileGr[j].atom_number].endpoint &&
                         ( MobileGr[j].forbidden == forbidden_mask ) &&
                         jN1 < 0)
                    {
                        jN1 = j;
                        n++;
                    }
                    else
                    {
                        if (MobileGr[j].bond_type == BOND_TYPE_SINGLE &&
                              MobileGr[j].num_bonds == 2 &&
                              MobileGr[j].bonds_valence == 3 &&
                              at[MobileGr[j].atom_number].endpoint &&
                              !( MobileGr[j].forbidden & forbidden_mask ) &&
                              jN2 < 0)
                        {
                            jN2 = j;
                            n++;
                        }
                    }
                }
                else
                {
                    if (!( ( MobileGr[j].atom_type_pVA & ( EL_TYPE_N | EL_TYPE_P ) ) ||
                        (( MobileGr[j].atom_type_pVA & ( EL_TYPE_O | EL_TYPE_S ) ) &&
                           MobileGr[j].num_bonds > 1 )) &&
                            !( MobileGr[j].forbidden & forbidden_mask ) &&
                            MobileGr[j].bond_type == BOND_TYPE_SINGLE &&
                            jX < 0) /* djb-rwth: addressing LLVM warning */
                    {
                        jX = j;
                        n++;
                    }
                }
            }
            if (jN1 < 0 || jN2 < 0)
            {
                goto case_5_9c_to_8c;
            }

            ev = pBNS->edge + pBNS->vert[i].iedge[MobileGr[jN1].ineigh];
            e = pBNS->edge + pVA[MobileGr[jN2].atom_number].nTautGroupEdge - 1;
            if (e->flow)
            {
                goto case_5_9c_to_8c; /* should not happen ??? */
            }
            pv1 = pBNS->vert + e->neighbor1;  /* must be jN2 */
            pv2 = pBNS->vert + ( e->neighbor1 ^ e->neighbor12 );
            /* djb-rwth: removing redundant code */
            ie1 = ie2 = -1;
            ev->forbidden &= inv_forbidden_mask;
            for (j = 0; j < pv1->num_adj_edges; j++)
            {
                ev1 = pBNS->edge + pv1->iedge[j];
                if (ev1->flow && !ev1->forbidden)
                {
                    ie1 = (int) ( ev1 - pBNS->edge );
                    pv1 = pBNS->vert + ( ev1->neighbor12 ^ ( pv1 - pBNS->vert ) );
                    break;
                }
            }
            for (j = 0; j < pv2->num_adj_edges; j++)
            {
                ev2 = pBNS->edge + pv2->iedge[j];
                if (ev2->flow && !ev2->forbidden)
                {
                    ie2 = (int) ( ev2 - pBNS->edge );
                    pv2 = pBNS->vert + ( ev2->neighbor12 ^ ( pv2 - pBNS->vert ) );
                    break;
                }
            }
            if (ie1 < 0 || ie2 < 0)
            {
                ev->forbidden |= forbidden_mask; /* failed; restore the forbidden bit */
                goto case_5_9c_to_8c;
            }
            e->flow++;
            e->forbidden |= forbidden_mask;
            ev1->flow--;
            ev2->flow--;
            pv1->st_edge.flow--;
            pv2->st_edge.flow--;
            pBNS->tot_st_flow -= 2;
            num_changes++;
            continue;
        }
    case_5_9c_to_8c: /* #4 */
            /*********************************************************************/
        if (3 == num_bonds_non_metal &&
             4 == bonds_valence_non_metal &&
             ( centerpoint_type == EL_TYPE_S ) &&
             0 == num_O + num_S && 3 == num_N && 0 == num_P &&
             0 == num_forbidden &&
             2 == num_diff_t_groups && 2 == num_mgroups && /* all neighbors belong to 2 t-groups */
             3 == num_eql_mobile_gr + num_dif_mobile_gr && /* all 3 neighbors belong to t-groups */
             2 == num_donor_endpoints && 1 == num_acceptor_endpoints &&
             2 == num_donors && 1 == num_acceptors)
        {
            /********************************************************
             ***         InChI Tech. Man., Table 5, case 8c->9c   ***
             ********************************************************
                is an endpoint --->                  O  =  O, S, Se, Te
                tg1   NH2(X)             NH2(X)      S  =  S, Se, Te
             \       / pv1  pv2 \       /            f  =  fixed bond
              \(1)  /  C=====Z   \     /  C-----ZH   tg =  Mobile-H vertex
               N===S   |     |    N===S  ||     ||   X  =  is N not an endpoint;
            is an   \  |ev1  | ev2     \ ||     ||  -X is not terminal -O,-S,-Se,-Te or
            endpoint   \ |  e  |          \||  e  ||        any N, P, As
            tg1      (2)NH=====tg          N------tg   C is a centerpoint of a t-group
                       is an                   f       N, N, X, fixed single
                     endpoint                          =====================
                     tg2
              Problem:
                N (1) and NH2 are Mobile-H group 1 endpoiints, NH (2) is a Mobile-H group 2 endpoint
                Unfixed bonds N==S--NH(2) allows the two Mobile H groups to merge
                hence prevents the correct structure restoration:
                H can migrate from NH (2) to N (1) because S-NH(1) bond is not fixed
              Solution:
                Move H from NH(2) to =Z to make S-NH(2) bond fixed (Table 5, case 8c)
                (this unfixes the bond, see fix_special_bonds(...) )
              *********************************************************/
            int jN1 = -1, jN2 = -1, jX = -1, n = 0;
            /* find t-group that is represented by only one neighbor */
            for (j = 0, k = 0; j < num_mgroups; j++)
            {
                if (1 == MGroups[k].num && MGroups[k].group_number)
                {
                    k = MGroups[k].group_number;
                    break;
                }
            }
            if (!k)
            {
                goto case_5_9c_to_9d;
            }
            for (j = 0; j < num_endpoints; j++)
            {
                if (( MobileGr[j].atom_type_pVA & EL_TYPE_MASK ) == EL_TYPE_N)
                {
                    if (MobileGr[j].bond_type == BOND_TYPE_DOUBLE &&
                         at[MobileGr[j].atom_number].endpoint &&
                         at[MobileGr[j].atom_number].endpoint != k &&
                         jN1 < 0)
                    {
                        jN1 = j;
                        n++;
                    }
                    else
                    {
                        if (MobileGr[j].bond_type == BOND_TYPE_SINGLE &&
                                MobileGr[j].num_bonds == 2 &&
                                MobileGr[j].bonds_valence == 2 &&
                                at[MobileGr[j].atom_number].endpoint == k &&
                                jN2 < 0)
                        {
                            jN2 = j;
                            n++;
                        }
                        else
                        {
                            if (MobileGr[j].bond_type == BOND_TYPE_SINGLE &&
                                  MobileGr[j].num_bonds <= 2 &&
                                  MobileGr[j].bonds_valence <= 3 &&
                                  at[MobileGr[j].atom_number].endpoint &&
                                  at[MobileGr[j].atom_number].endpoint != k &&
                                  jX < 0)
                            {
                                jX = j;
                                n++;
                            }
                        }
                    }
                }
            }
            if (n != 3)
            {
                goto case_5_9c_to_9d;
            }

            e = pBNS->edge + pVA[MobileGr[jN2].atom_number].nTautGroupEdge - 1;
            if (!e->flow)
            {
                goto case_5_9c_to_9d; /* should not happen ??? */
            }
            e->flow--;
            pBNS->vert[e->neighbor1].st_edge.flow--;
            pBNS->vert[e->neighbor1 ^ e->neighbor12].st_edge.flow--;
            pBNS->tot_st_flow -= 2;
            e->forbidden |= forbidden_mask;
            num_changes++;
            continue;
        }
    case_5_9c_to_9d: /* #6 */
            /*********************************************************************/
        if (3 == num_bonds_non_metal &&
             4 == bonds_valence_non_metal &&
             ( centerpoint_type == EL_TYPE_S ) &&
             0 == num_O + num_S && 3 == num_N && 0 == num_P &&
             0 == num_forbidden &&
             3 == num_mgroups && 2 == num_diff_t_groups &&
             2 == num_donor_endpoints && 0 == num_acceptor_endpoints &&
             2 == num_donors && 1 == num_acceptors)
        {
            /********************************************************
             ***         InChI Tech. Man., Table 5, case 9b->8b   ***
             ********************************************************
                 3(X)      --->         e2|          O  =  O, S, Se, Te
                  NH---is an              N======    S  =  S, Se, Te
            \       /   endpoint    \       /           f  =  fixed bond
             \ 1   /  C=====Z        \  f  /  C-----Z   tg =  Mobile-H vertex
              N===S   |     |         N===S  ||     ||  X  =  is N not an endpoint;
            is an  ev  \  |     |           ev \ ||     || -X is not terminal -O,-S,-Se,-Te or
            endpoint     2\ |  e1 |               \||  e1 ||       any N, P, As
                           NH=====tg               N------tg
                        is an                          f      N, N, X, fixed double
                     endpoint                                 =====================

                     Problem:
                       N1, N2, and N3 are Mobile-H endpoints and belong to the same Mobile-H group.
                       Fixed bond N1==S prevents the correct structure restoration:
                       H cannot migrate N3->N2->N1 because N1=S bond is fixed
                     Solution:
                       Move mobile H to N2 and N3 to make N1=S bond unfixed (Table 5, case 9c)
                       (see fix_special_bonds(...) for details )
                     *********************************************************/
            int jN1 = -1, jN2 = -1, jX = -1, n = 0;
            for (j = 0; j < num_endpoints; j++)
            {
                if (( MobileGr[j].atom_type_pVA & EL_TYPE_MASK ) == EL_TYPE_N)
                {
                    if (MobileGr[j].bond_type == BOND_TYPE_DOUBLE &&
                         !at[MobileGr[j].atom_number].endpoint &&
                         !( MobileGr[j].forbidden & forbidden_mask ) &&
                         jN1 < 0)
                    {
                        jN1 = j;
                        n++;
                    }
                    else
                    {
                        if (MobileGr[j].bond_type == BOND_TYPE_SINGLE &&
                                MobileGr[j].num_bonds == 2 &&
                                MobileGr[j].bonds_valence <= 3 &&
                                at[MobileGr[j].atom_number].endpoint &&
                                !( MobileGr[j].forbidden & forbidden_mask ))
                        {
                            if (jN2 < 0)
                            {
                                jN2 = j;
                                n++;
                            }
                            else
                            {
                                if (jX < 0)
                                {
                                    jX = j;
                                    n++;
                                }
                            }
                        }
                    }
                }
            }
            if (n != 3)
            {
                goto case_end;
            }
            ev = pBNS->edge + pBNS->vert[i].iedge[MobileGr[jN1].ineigh];
            if (!ev->flow) /* 2017-02-15 Fixed typo ("!e->flow") which has been here since v. 1.01 */
            {
                goto case_end;
            }
            e1 = pBNS->edge + pVA[MobileGr[jN2].atom_number].nTautGroupEdge - 1;
            if (!e1->flow)
            {
                goto case_end; /* should not happen ??? */
            }
            e2 = pBNS->edge + pVA[MobileGr[jX].atom_number].nTautGroupEdge - 1;
            if (!e2->flow)
            {
                goto case_end; /* should not happen ??? */
            }
            /* take care of edge e1 */
            e = e1;
            e->flow--;
            pBNS->vert[e->neighbor1].st_edge.flow--;
            pBNS->vert[e->neighbor1 ^ e->neighbor12].st_edge.flow--;
            pBNS->tot_st_flow -= 2;
            e->forbidden |= forbidden_mask;
            num_changes++;
            /* take care of edge e2 */
            e = e2;
            e->flow--;
            pBNS->vert[e->neighbor1].st_edge.flow--;
            pBNS->vert[e->neighbor1 ^ e->neighbor12].st_edge.flow--;
            pBNS->tot_st_flow -= 2;
            e->forbidden |= forbidden_mask;
            num_changes++;
            /* take care of edge ev: do not let it change */
            ev->forbidden |= forbidden_mask;
            continue;
        }
    case_end:;
    }

/*exit_function:*/
    return num_changes;
}


/****************************************************************************
 Replace ambiguous neutral (+)edge->flow=0, (-)edge->flow=1
 with (+)edge->flow=1, (-)edge->flow=0
****************************************************************************/
int RearrangePlusMinusEdgesFlow( BN_STRUCT *pBNS,
                                 BN_DATA *pBD,
                                 VAL_AT *pVA,
                                 ALL_TC_GROUPS *pTCGroups,
                                 int forbidden_edge_mask )
{
    int ret, ePlus, eMinus;
    EDGE_LIST NewlyFixedEdges;
    BNS_EDGE *pPlus, *pMinus;
    int i, k1, k2, num_found, num_tot, delta, v1, v2;

    ret = 0;

    AllocEdgeList( &NewlyFixedEdges, EDGE_LIST_CLEAR );
    for (i = 0, num_found = num_tot = 0; i < pBNS->num_atoms; i++)
    {
        eMinus = pVA[i].nCMinusGroupEdge - 1;
        ePlus = pVA[i].nCPlusGroupEdge - 1;
        num_tot += ( eMinus >= 0 ) + ( ePlus >= 0 );
        if (eMinus >= 0 && ePlus >= 0)
        {
            pPlus = pBNS->edge + ePlus;
            pMinus = pBNS->edge + eMinus;
            if (( pMinus->flow ) > 0 && ( pPlus->cap - pPlus->flow ) > 0) /* djb-rwth: removing redundant code */
            {
                num_found++;
            }
        }
    }
    if (!num_found)
    {
        goto exit_function;
    }
    if ((ret = AllocEdgeList( &NewlyFixedEdges, num_tot + pBNS->num_bonds ))) /* djb-rwth: addressing LLVM warning */
    {
        goto exit_function;
    }

    for (i = 0, num_tot = 0; i < pBNS->num_atoms; i++) /* djb-rwth: removing redundant code */
    {
        eMinus = pVA[i].nCMinusGroupEdge - 1;
        ePlus = pVA[i].nCPlusGroupEdge - 1;
        num_tot += ( eMinus >= 0 ) + ( ePlus >= 0 );
        if (eMinus >= 0 && ePlus >= 0)
        {
            pPlus = pBNS->edge + ePlus;
            pMinus = pBNS->edge + eMinus;
            if (( k1 = pMinus->flow ) > 0 && ( k2 = pPlus->cap - pPlus->flow ) > 0)
            {
                /* rearrange */
                v1 = pMinus->neighbor1;
                v2 = pMinus->neighbor12 ^ v1;
                delta = inchi_min( k1, k2 );
                pMinus->flow -= delta;
                pBNS->vert[v1].st_edge.flow -= delta;
                pBNS->vert[v2].st_edge.flow -= delta;
                pBNS->tot_st_flow -= 2 * delta;
            }
            /* fix charges */
            pPlus->forbidden |= forbidden_edge_mask;
            pMinus->forbidden |= forbidden_edge_mask;
            if (( ret = AddToEdgeList( &NewlyFixedEdges, eMinus, 0 ) ) ||
                ( ret = AddToEdgeList( &NewlyFixedEdges, ePlus, 0 ) ))
            {
                goto exit_function;
            }
        }
        else
        {
            if (eMinus >= 0)
            {
                /* fix charges */
                pMinus = pBNS->edge + eMinus;
                pMinus->forbidden |= forbidden_edge_mask;
                if ((ret = AddToEdgeList( &NewlyFixedEdges, eMinus, 0 ))) /* djb-rwth: addressing LLVM warning */
                {
                    goto exit_function;
                }
            }
            else
            {
                if (ePlus >= 0)
                {
                    /* fix charges */
                    pPlus = pBNS->edge + ePlus;
                    pPlus->forbidden |= forbidden_edge_mask;
                    if ((ret = AddToEdgeList( &NewlyFixedEdges, ePlus, 0 ))) /* djb-rwth: addressing LLVM warning */
                    {
                        goto exit_function;
                    }
                }
            }
        }
    }
    for (i = 0; i < pBNS->num_bonds; i++)
    {
        pBNS->edge[i].forbidden |= forbidden_edge_mask;
        if ((ret = AddToEdgeList( &NewlyFixedEdges, i, 0 ))) /* djb-rwth: addressing LLVM warning */
        {
            goto exit_function;
        }
    }
    ret = RunBnsRestoreOnce( pBNS, pBD, pVA, pTCGroups );
    RemoveForbiddenEdgeMask( pBNS, &NewlyFixedEdges, forbidden_edge_mask );
    if (ret < 0)
    {
        goto exit_function;
    }

exit_function:
    AllocEdgeList( &NewlyFixedEdges, EDGE_LIST_FREE );

    return ret;
}


/****************************************************************************/
int IncrementZeroOrderBondsToHeteroat( BN_STRUCT *pBNS,
                                       BN_DATA *pBD,
                                       StrFromINChI *pStruct,
                                       inp_ATOM *at,
                                       inp_ATOM *at2,
                                       VAL_AT *pVA,
                                       ALL_TC_GROUPS *pTCGroups,
                                       int *pnNumRunBNS,
                                       int *pnTotalDelta,
                                       int forbidden_edge_mask )
{
#define FIX_BOND_ADD_ALLOC 128
    Vertex     vPathStart, vPathEnd;
    int        nPathLen, nDeltaH, nDeltaCharge, nNumVisitedAtoms;
    BNS_EDGE   *pe, *peZero, *peNeighMeigh = NULL, *peMeFlower;
    BNS_VERTEX *pMeFlower = NULL, *pNeigh = NULL, *pNeighNeigh = NULL;

    int i, j, k, ret2, ret, bFixedCarbonCharges, num_changes, bSuccess;
    int num_at = pStruct->num_atoms;
    int num_deleted_H = pStruct->num_deleted_H;
    int len_at = num_at + num_deleted_H;
    int inv_forbidden_edge_mask = ~forbidden_edge_mask;
    Vertex vMeFlower0, vNeigh, vNeighMeigh = NO_VERTEX;

    EDGE_LIST CarbonChargeEdges;
    EDGE_LIST NewlyFixedEdges;

    ret = 0;
    num_changes = 0;

    bFixedCarbonCharges = 0;
    AllocEdgeList( &CarbonChargeEdges, EDGE_LIST_CLEAR );
    AllocEdgeList( &NewlyFixedEdges, EDGE_LIST_CLEAR );

    if (!pTCGroups->num_metal_atoms ||
         0 > ( k = pTCGroups->nGroup[TCG_MeFlower0] ) ||
         0 > ( vMeFlower0 = pTCGroups->pTCG[k].nVertexNumber ))
    {
        goto exit_function;
    }

    memcpy(at2, at, len_at * sizeof(at2[0]));
    pStruct->at = at2;
    ret2 = CopyBnsToAtom( pStruct, pBNS, pVA, pTCGroups, 1 );
    pStruct->at = at;
    if (ret2 < 0)
    {
        ret = ret2;
        goto exit_function;
    }
    for (i = 0; i < num_at; i++)
    {
        if (!pVA[i].cMetal || pVA[i].nMetalGroupEdge <= 0)
        {
            continue;
        }
        peMeFlower = pBNS->edge + pVA[i].nMetalGroupEdge - 1;
        if (vMeFlower0 != ( peMeFlower->neighbor12 ^ i ))
        {
            ret = RI_ERR_PROGR;
            goto exit_function;
        }
        pMeFlower = pBNS->vert + vMeFlower0;

        for (j = 0; j < at2[i].valence; j++)
        {
            if (!peMeFlower->flow)
            {
                break; /* cannot do anything */
            }
            if (!( at2[i].bond_type[j] & BOND_TYPE_MASK ))
            {
                /* found a zero order bond */
                if (!bFixedCarbonCharges)
                {
                    /* do not let carbon atoms get charged */
                    if (0 > ( ret = ForbidCarbonChargeEdges( pBNS, pTCGroups, &CarbonChargeEdges, forbidden_edge_mask ) ))
                    {
                        goto exit_function;
                    }
                    bFixedCarbonCharges++;
                }
                peZero = pBNS->edge + pBNS->vert[i].iedge[j];
                if (peZero->flow)
                {
                    ret = RI_ERR_PROGR;
                    goto exit_function;
                }
                /* fix other edges */
                for (k = 0; k < at2[i].valence; k++)
                {
                    pe = pBNS->edge + pBNS->vert[i].iedge[k];
                    if (pe->flow == 1 && !( pe->forbidden & forbidden_edge_mask ))
                    {
                        if ((ret = AddToEdgeList( &NewlyFixedEdges, (int) ( pe - pBNS->edge ), FIX_BOND_ADD_ALLOC ))) /* djb-rwth: addressing LLVM warning */
                        {
                            goto exit_function;
                        }
                        pe->forbidden |= forbidden_edge_mask;
                    }
                }
                /* do not create =N(+)= in a ring or #O(+) terminal */
                for (k = 0; k < num_at; k++)
                {
                    if (!pVA[k].cMetal && pVA[k].cNumValenceElectrons == 5 &&
                         at2[k].valence == 2 && !at2[k].num_H && pVA[k].cMinRingSize <= 6 &&
                         pVA[k].nCPlusGroupEdge > 0 &&
                         ( pe = pBNS->edge + pVA[k].nCPlusGroupEdge - 1 )->flow == 1 &&
                         !( pe->forbidden & forbidden_edge_mask ))
                    {

                        if ((ret = AddToEdgeList( &NewlyFixedEdges, (int) ( pe - pBNS->edge ), FIX_BOND_ADD_ALLOC ))) /* djb-rwth: addressing LLVM warning */
                        {
                            goto exit_function;
                        }
                        pe->forbidden |= forbidden_edge_mask;
                    }
                }

                /* metal's neighbor connected by a zero-order bond */
                pNeigh = pBNS->vert + ( vNeigh = at2[i].neighbor[j] );
                /*for ( k = 0; k < pNeigh->num_adj_edges; k ++ )*/
                for (k = pNeigh->num_adj_edges - 1; 0 <= k; k--)
                {
                    peNeighMeigh = pBNS->edge + pNeigh->iedge[k];
                    if (!peNeighMeigh->flow)
                    {
                        continue;
                    }
                    vNeighMeigh = peNeighMeigh->neighbor12 ^ vNeigh;
                    if (vNeighMeigh != i && vNeighMeigh != vMeFlower0)
                    {
                        /* metal neighbor's neighbor connected by a not-zero-order bond */
                        pNeighNeigh = pBNS->vert + vNeighMeigh;
                        break; /* found */
                    }
                }
                if (k < 0)
                {
                    continue; /* neighbor not found */
                }
                peZero->flow++;
                peZero->forbidden |= forbidden_edge_mask;
                peMeFlower->flow--;
                peNeighMeigh->flow--;
                pMeFlower->st_edge.flow--;
                pNeighNeigh->st_edge.flow--;
                pBNS->tot_st_flow -= 2;
                /* test */
                bSuccess = 0;
                ret = RunBnsTestOnce( pBNS, pBD, pVA, &vPathStart, &vPathEnd, &nPathLen,
                                      &nDeltaH, &nDeltaCharge, &nNumVisitedAtoms );

                if (ret == 1 && ( (vPathEnd == vMeFlower0 && vPathStart == vNeighMeigh) ||
                    (vPathEnd == vNeighMeigh && vPathStart == vMeFlower0) ) && abs( nDeltaCharge ) <= 2) /* djb-rwth: addressing LLVM warnings */
                {
                    ret = RunBnsRestoreOnce( pBNS, pBD, pVA, pTCGroups );
                    if (ret > 0)
                    {
                        ( *pnNumRunBNS )++;
                        *pnTotalDelta += ret;
                        num_changes++;
                        bSuccess = ret;
                    }
                    if ((ret = AddToEdgeList( &NewlyFixedEdges, (int) ( peZero - pBNS->edge ), FIX_BOND_ADD_ALLOC ))) /* djb-rwth: addressing LLVM warning */
                    {
                        goto exit_function;
                    }
                }
                else
                {
                    peZero->flow--;
                    peZero->forbidden &= inv_forbidden_edge_mask;
                    peMeFlower->flow++;
                    peNeighMeigh->flow++;
                    pMeFlower->st_edge.flow++;
                    pNeighNeigh->st_edge.flow++;
                    pBNS->tot_st_flow += 2;
                }
                RemoveForbiddenEdgeMask( pBNS, &NewlyFixedEdges, forbidden_edge_mask );
                NewlyFixedEdges.num_edges = 0;
                if (bSuccess)
                {
                    /* update at2[] */
                    memcpy(at2, at, len_at * sizeof(at2[0]));
                    pStruct->at = at2;
                    ret2 = CopyBnsToAtom( pStruct, pBNS, pVA, pTCGroups, 1 );
                    pStruct->at = at;
                    if (ret2 < 0)
                    {
                        ret = ret2;
                        goto exit_function;
                    }
                }
            }
        }
    }
    ret = num_changes;

exit_function:
    RemoveForbiddenEdgeMask( pBNS, &CarbonChargeEdges, forbidden_edge_mask );
    RemoveForbiddenEdgeMask( pBNS, &NewlyFixedEdges, forbidden_edge_mask );
    AllocEdgeList( &CarbonChargeEdges, EDGE_LIST_FREE );
    AllocEdgeList( &NewlyFixedEdges, EDGE_LIST_FREE );

    return ret;
}


/****************************************************************************
        NH2                NH2
           \                  \
            C==S(+)-   =>      C(+)-S-   where NH2 are not tautomeric
           /                  /
        NH2                NH2
****************************************************************************/
int MovePlusFromS2DiaminoCarbon( BN_STRUCT *pBNS,
                                 BN_DATA *pBD,
                                 StrFromINChI *pStruct,
                                 inp_ATOM *at,
                                 inp_ATOM *at2,
                                 VAL_AT *pVA,
                                 ALL_TC_GROUPS *pTCGroups,
                                 int *pnNumRunBNS,
                                 int *pnTotalDelta,
                                 int forbidden_edge_mask )
{
    int i, j, k, ret, ret2; /* djb-rwth: removing redundant variables */
    int delta;
    EdgeIndex        ePlusS, ePlusC, eMinusC, e;
    BNS_VERTEX *pvS, *pvC, *pv1, *pv2;
    BNS_EDGE   *pePlusS, *pePlusC, *pe1, *pe2, *peCN[3], *peSC, *pe;
    Vertex     vC, vN;

    int num_at = pStruct->num_atoms;
    int num_deleted_H = pStruct->num_deleted_H;
    int len_at = num_at + num_deleted_H;

    Vertex     vPathStart, vPathEnd, v1, v2;
    int        nPathLen, nDeltaH, nDeltaCharge, nNumVisitedAtoms;

    EDGE_LIST AllChargeEdges;

    ret = 0;
    /* djb-rwth: removing redundant code */

    AllocEdgeList( &AllChargeEdges, EDGE_LIST_CLEAR );

    memcpy(at2, at, len_at * sizeof(at2[0]));
    pStruct->at = at2;
    ret2 = CopyBnsToAtom( pStruct, pBNS, pVA, pTCGroups, 1 );
    pStruct->at = at;
    if (ret2 < 0)
    {
        ret = ret2;
        goto exit_function;
    }
    /* find (NH2)C=S(+) */
    for (i = 0; i < num_at; i++)
    {
        pvS = pBNS->vert + i; /* djb-rwth: avoiding unsequenced modification and access */
        if (!pVA[i].cMetal && pVA[i].cNumValenceElectrons == 6 &&
             at2[i].valence == 2 &&
             pvS->st_edge.cap == pvS->st_edge.flow &&
             0 <= ( ePlusS = pVA[i].nCPlusGroupEdge - 1 ) && !( pePlusS = pBNS->edge + ePlusS )->flow && /* S(+) */
             ( pe1 = pBNS->edge + pvS->iedge[0] )->flow +
             ( pe2 = pBNS->edge + pvS->iedge[1] )->flow == 1 /* -S(+)= */ &&
             pVA[vC = ( peSC = pe1->flow ? pe1 : pe2 )->neighbor12 ^ i].cNumValenceElectrons == 4 &&
             at2[vC].valence == 3 &&
             0 <= ( ePlusC = pVA[vC].nCPlusGroupEdge - 1 ) && ( pePlusC = pBNS->edge + ePlusC )->flow &&
             !( 0 <= ( eMinusC = pVA[vC].nCMinusGroupEdge - 1 ) && pBNS->edge[eMinusC].flow ))
        {
            /* found >C=S(+)- */
            pvC = pBNS->vert + vC;
            for (j = k = 0; j < at[vC].valence; j++)
            {
                if (peSC != ( peCN[k] = pBNS->edge + pvC->iedge[j] ) && !peCN[k]->flow)
                {
                    k++; /* a single bond from C */
                }
            }
            if (k != 2)
            {
                continue;
            }
            for (j = 0; j < k; j++)
            {
                vN = peCN[j]->neighbor12 ^ vC;
                if (pVA[vN].cNumValenceElectrons != 5 ||
                     pBNS->vert[vN].st_edge.cap != pBNS->vert[vN].st_edge.flow ||
                     at2[vN].num_H != 2 ||
                     at2[vN].endpoint || ( pStruct->endpoint && pStruct->endpoint[vN] ))
                {
                    break; /* does not fit the pattern */
                }
            }
            if (j != k)
            {
                continue;
            }
            /* fix all charges */
            if (!AllChargeEdges.num_edges)
            {
                for (j = 0; j < num_at; j++)
                {
                    if (0 <= ( e = pVA[j].nCPlusGroupEdge - 1 ) && !pBNS->edge[e].forbidden &&
                        ( ret = AddToEdgeList( &AllChargeEdges, e, 2 * num_at ) ))
                    {
                        goto exit_function;
                    }
                    if (0 <= ( e = pVA[j].nCMinusGroupEdge - 1 ) && !pBNS->edge[e].forbidden &&
                        ( ret = AddToEdgeList( &AllChargeEdges, e, 2 * num_at ) ))
                    {
                        goto exit_function;
                    }
                }
            }
            SetForbiddenEdgeMask( pBNS, &AllChargeEdges, forbidden_edge_mask );
            pePlusS->forbidden &= ~forbidden_edge_mask;
            pe = pePlusC;
            if (!pe->flow)
                continue;
            delta = 1;
            pv1 = pBNS->vert + ( v1 = pe->neighbor1 );
            pv2 = pBNS->vert + ( v2 = pe->neighbor12 ^ v1 );

            pe->flow -= delta;
            pv1->st_edge.flow -= delta;
            pv2->st_edge.flow -= delta;
            pBNS->tot_st_flow -= 2 * delta;

            ret = RunBnsTestOnce( pBNS, pBD, pVA, &vPathStart, &vPathEnd, &nPathLen,
                                  &nDeltaH, &nDeltaCharge, &nNumVisitedAtoms );

            if (ret == 1 && ( (vPathEnd == v1 && vPathStart == v2) ||
                (vPathEnd == v2 && vPathStart == v1) ) && nDeltaCharge == -1) /* djb-rwth: addressing LLVM warnings */
            {
                /* Remover (+)charge from S => nDeltaCharge == -1 */
                /* Flow change on pe (+)charge edge (atom S) is not known to RunBnsTestOnce()) */
                ret = RunBnsRestoreOnce( pBNS, pBD, pVA, pTCGroups );
                if (ret > 0)
                {
                    ( *pnNumRunBNS )++;
                    /* djb-rwth: removing redundant code */
                }
            }
            else
            {
                pe->flow += delta;
                pv1->st_edge.flow += delta;
                pv2->st_edge.flow += delta;
                pBNS->tot_st_flow += 2 * delta;
            }
            RemoveForbiddenEdgeMask( pBNS, &AllChargeEdges, forbidden_edge_mask );
        }
    }
exit_function:
    AllocEdgeList( &AllChargeEdges, EDGE_LIST_FREE );

    return ret;
}


/****************************************************************************/
int EliminateChargeSeparationOnHeteroatoms( BN_STRUCT *pBNS,
                                            BN_DATA *pBD,
                                            StrFromINChI *pStruct,
                                            inp_ATOM *at,
                                            inp_ATOM *at2,
                                            VAL_AT *pVA,
                                            ALL_TC_GROUPS *pTCGroups,
                                            int *pnNumRunBNS,
                                            int *pnTotalDelta,
                                            int forbidden_edge_mask,
                                            int forbidden_stereo_edge_mask )
    /********* Avoid charge separation on heteroatoms ******************/
{
    int i, j, k, ret, ret2, num_pos, num_neg, num_min = 0, bFixedCarbonCharges;
    int vPlusSuper;  /* (+)super vertex */
    int ePlusSuper;  /* edge from vPlusSuper to (+/-) */
    int vPlusMinus;  /* (+/-) vertex */
    int nDeltaPlus1, nDeltaMinus1, delta;
    BNS_VERTEX *pvPlusSuper, *pvPlusMinus;
    BNS_EDGE   *pEdge;

    int num_at = pStruct->num_atoms;
    int num_deleted_H = pStruct->num_deleted_H;
    int len_at = num_at + num_deleted_H;
    int inv_forbidden_edge_mask = ~forbidden_edge_mask;

    Vertex     vPathStart, vPathEnd;
    int        nPathLen, nDeltaH, nDeltaCharge, nNumVisitedAtoms;

    EDGE_LIST FixedLargeRingStereoEdges, CarbonChargeEdges;

    ret = 0;

    AllocEdgeList( &FixedLargeRingStereoEdges, EDGE_LIST_CLEAR );
    AllocEdgeList( &CarbonChargeEdges, EDGE_LIST_CLEAR );
    bFixedCarbonCharges = 0;

    if (forbidden_stereo_edge_mask)
    {
        for (i = 0; i < num_at; i++)
        {
            for (j = 0; j < at2[i].valence; j++)
            {
                if (pBNS->edge[k = pBNS->vert[i].iedge[j]].forbidden == forbidden_stereo_edge_mask)
                {
                    int nMinRingSize = is_bond_in_Nmax_memb_ring( at2, i, j, pStruct->pbfsq->q,
                                                             pStruct->pbfsq->nAtomLevel,
                                                             pStruct->pbfsq->cSource, 99 /* max ring size */ );
                    if (0 < nMinRingSize && ( ret = AddToEdgeList( &FixedLargeRingStereoEdges, k, 64 ) ))
                    {
                        goto exit_function;
                    }
                }
            }
        }
        if (!FixedLargeRingStereoEdges.num_edges)
        {
            goto exit_function;
        }
        else
        {
             /* allow stereobonds in rings change */
            RemoveForbiddenEdgeMask( pBNS, &FixedLargeRingStereoEdges, forbidden_stereo_edge_mask );
        }
    }

    memcpy(at2, at, len_at * sizeof(at2[0]));
    pStruct->at = at2;
    ret2 = CopyBnsToAtom( pStruct, pBNS, pVA, pTCGroups, 1 );
    pStruct->at = at;
    if (ret2 < 0)
    {
        ret = ret2;
        goto exit_function;
    }
    /* count charges */
    num_pos = num_neg = 0;
    for (i = 0; i < num_at; i++)
    {
        if (!pVA[i].cMetal && !at2[i].radical)
        {
            num_pos += ( at2[i].charge > 0 );
            num_neg += ( at2[i].charge < 0 );
        }
    }
    num_min = inchi_min( num_pos, num_neg );


    if (num_min &&
        ( k = pTCGroups->nGroup[TCG_Plus] ) >= 0 &&
        ( ePlusSuper = pTCGroups->pTCG[k].nForwardEdge ) > 0 &&
        ( vPlusSuper = pTCGroups->pTCG[k].nVertexNumber ) >= num_at &&
         !( pEdge = pBNS->edge + ePlusSuper )->forbidden)
    {

        vPlusMinus = pEdge->neighbor12 ^ vPlusSuper;
        pvPlusSuper = pBNS->vert + vPlusSuper;
        pvPlusMinus = pBNS->vert + vPlusMinus;
        num_min = inchi_min( num_min, pEdge->flow );
        nDeltaPlus1 = pvPlusSuper->st_edge.cap - pvPlusSuper->st_edge.flow;
        nDeltaMinus1 = pvPlusMinus->st_edge.cap - pvPlusMinus->st_edge.flow;
        if (num_min && ( !nDeltaPlus1 && !nDeltaMinus1 ))
        {
            if (!bFixedCarbonCharges)
            { /* 02-02-2006 */
              /* do not let carbon atoms get charged */
                if (0 > ( ret = ForbidCarbonChargeEdges( pBNS, pTCGroups, &CarbonChargeEdges, forbidden_edge_mask ) ))
                {
                    goto exit_function;
                }
                bFixedCarbonCharges++;
            }
            delta = 1;
            pEdge->forbidden |= forbidden_edge_mask;
            pBNS->edge_forbidden_mask |= forbidden_edge_mask;
            for (i = 0; i < num_min; i += delta)
            {
                /* cancel 1 pair of charges at a time   */
                /* an attempt to cancel all at once may */
                /* convert a pair of N(IV)(+) into a pair of N(V) neutral with total charge reduced by 2 */
                pEdge->flow -= delta;
                pvPlusSuper->st_edge.flow -= delta;
                pvPlusMinus->st_edge.flow -= delta;
                pBNS->tot_st_flow -= 2 * delta;
                /* test for charhe cancellation */
                ret = RunBnsTestOnce( pBNS, pBD, pVA, &vPathStart, &vPathEnd, &nPathLen,
                                      &nDeltaH, &nDeltaCharge, &nNumVisitedAtoms );
                if (ret < 0)
                {
                    goto exit_function;
                }
                if (ret == 1 && ( (vPathEnd == vPlusSuper && vPathStart == vPlusMinus) ||
                    (vPathEnd == vPlusMinus && vPathStart == vPlusSuper) ) && nDeltaCharge < 0) /* djb-rwth: addressing LLVM warnings */
                {
                    ret = RunBnsRestoreOnce( pBNS, pBD, pVA, pTCGroups );
                    ( *pnNumRunBNS )++;
                    if (ret < 0)
                    {
                        goto exit_function;
                    }
                    else
                        if (ret == 1)
                        {
                            *pnTotalDelta += ret;
                        }
                        else
                        {
                            ret = RI_ERR_PROGR;
                            goto exit_function;
                        }
                }
                else
                {
                    pEdge->flow += delta;
                    pvPlusSuper->st_edge.flow += delta;
                    pvPlusMinus->st_edge.flow += delta;
                    pBNS->tot_st_flow += 2 * delta;
                    break;
                }
            }
            num_min -= i; /* how many pairs of charges left */
            pEdge->forbidden &= inv_forbidden_edge_mask;
        }
        nDeltaPlus1 = pvPlusSuper->st_edge.cap - pvPlusSuper->st_edge.flow;
        nDeltaMinus1 = pvPlusMinus->st_edge.cap - pvPlusMinus->st_edge.flow;
        if (num_min > 1 && ( !nDeltaPlus1 && !nDeltaMinus1 ))
        {
            delta = 2;
            pEdge->forbidden |= forbidden_edge_mask;
            pBNS->edge_forbidden_mask |= forbidden_edge_mask;
            for (i = 0; i < num_min; i += delta)
            {
                /* cancel 2 pairs of opposite charges at a time   */
                /* 1. test cancellation of a pair of (+) charges */
                pvPlusSuper->st_edge.cap += delta;
                pBNS->tot_st_cap += delta;
                ret = RunBnsTestOnce( pBNS, pBD, pVA, &vPathStart, &vPathEnd, &nPathLen,
                                      &nDeltaH, &nDeltaCharge, &nNumVisitedAtoms );
                if (ret < 0)
                {
                    goto exit_function;
                }
                pvPlusSuper->st_edge.cap -= delta;
                pBNS->tot_st_cap -= delta;
                if (ret != 1 || ( vPathEnd != vPlusSuper || vPathStart != vPlusSuper ) || nDeltaCharge >= 0)
                {
                    break;
                }
                /* 2. test cancellation of a pair of (-) charges */
                pvPlusMinus->st_edge.cap += delta;
                pBNS->tot_st_cap += delta;
                ret = RunBnsTestOnce( pBNS, pBD, pVA, &vPathStart, &vPathEnd, &nPathLen,
                                      &nDeltaH, &nDeltaCharge, &nNumVisitedAtoms );
                if (ret < 0)
                {
                    goto exit_function;
                }
                pvPlusMinus->st_edge.cap -= delta;
                pBNS->tot_st_cap -= delta;
                if (ret != 1 || ( vPathEnd != vPlusMinus || vPathStart != vPlusMinus ) || nDeltaCharge >= 0)
                {
                    break;
                }
                /* 3. Actually cancel the pair of charges */
                pEdge->flow -= delta;
                pvPlusSuper->st_edge.flow -= delta;
                pvPlusMinus->st_edge.flow -= delta;
                pBNS->tot_st_flow -= 2 * delta;
                ret = RunBnsRestoreOnce( pBNS, pBD, pVA, pTCGroups );
                ( *pnNumRunBNS )++;
                if (ret < 0)
                {
                    goto exit_function;
                }
                else
                {
                    if (ret == 2)
                    {
                        *pnTotalDelta += ret;
                    }
                    else
                    {
                        ret = RI_ERR_PROGR;
                        goto exit_function;
                    }
                }
            }
            num_min -= i; /* how many pairs of charges left */
            pEdge->forbidden &= inv_forbidden_edge_mask;
        }
    }
    memcpy(at2, at, len_at * sizeof(at2[0]));
    pStruct->at = at;

exit_function:
    if (bFixedCarbonCharges)
    {
        RemoveForbiddenEdgeMask( pBNS, &CarbonChargeEdges, forbidden_edge_mask );
        AllocEdgeList( &CarbonChargeEdges, EDGE_LIST_FREE );
    }
    if (forbidden_stereo_edge_mask && FixedLargeRingStereoEdges.num_edges)
    {
        SetForbiddenEdgeMask( pBNS, &FixedLargeRingStereoEdges, forbidden_stereo_edge_mask );
    }
    AllocEdgeList( &FixedLargeRingStereoEdges, EDGE_LIST_FREE );

    return ret < 0 ? ret : num_min;
}


#if (MOVE_CHARGES_FROM_HETEREO_TO_METAL == 1 )


/****************************************************************************/
int MoveChargeFromHeteroatomsToMetals( BN_STRUCT *pBNS,
                                       BN_DATA *pBD,
                                       StrFromINChI *pStruct,
                                       inp_ATOM *at,
                                       inp_ATOM *at2,
                                       VAL_AT *pVA,
                                       ALL_TC_GROUPS *pTCGroups,
                                       int *pnNumRunBNS,
                                       int *pnTotalDelta,
                                       int forbidden_edge_mask )
    /********* Avoid charge separation on heteroatoms ******************/
{
    int i, k, ret, ret2, num_pos, num_neg, num_min;
    int vPlusSuper, vMinusSuper;  /* (+), (-) super vertices */
    int ePlusSuper, eMinusSuper;  /* edges from vPlusSuper or vMinusSuper to (+/-) */
    int vPlMn;  /* (+/-) vertex */
    int vPlusHeteroat, vMinusHeteroat; /* (+), (-) heteroatom vertices */
    int ePlusHeteroat, eMinusHeteroat; /* edges from (+) or (-) heteroatom vertex to super (+) or (-) */
    int vPlusCarbons, vMinusCarbons; /* (+), (-) carbons vertices */
    int ePlusCarbons, eMinusCarbons; /* edges from (+), (-) carbons vertices to super (+) or (-) */
    int vPlusMetals, vMinusMetals; /* (+), (-) carbons vertices */
    int ePlusMetals, eMinusMetals; /* edges from (+), (-) carbons vertices to super (+) or (-) */
    int eMinusHeteroToSuper;         /* edge (-)vHetero-[eMinusHeteroat]-Y-[eMinusHeteroToSuper]-(-)vPlusSuper */
    int v1, v2;
    int nDeltaPlus1, nDeltaMinus1, delta;
    BNS_VERTEX *pvPlusSuper, *pvMinusSuper, *pvPlMn;
    BNS_VERTEX *pvPlusHeteroat, *pvMinusHeteroat, *pvPlusCarbons, *pvMinusCarbons;
    BNS_VERTEX *pvPlusMetals, *pvMinusMetals;
    BNS_EDGE   *pEdgePlusHeteroat, *pEdgeMinusHeteroat, *pEdgeMinusHeteroToSuper;
    BNS_EDGE   *pEdgePlusCarbons, *pEdgeMinusCarbons, *pEdgePlusMetals, *pEdgeMinusMetals;
    BNS_EDGE   *pEdgePlusSuper, *pEdgeMinusSuper;

    int num_at = pStruct->num_atoms;
    int num_deleted_H = pStruct->num_deleted_H;
    int len_at = num_at + num_deleted_H;
    int inv_forbidden_edge_mask = ~forbidden_edge_mask;

    Vertex     vPathStart, vPathEnd;
    int        nPathLen, nDeltaH, nDeltaCharge, nNumVisitedAtoms;


    ret = 0;

    memcpy( at2, at, len_at * sizeof( at2[0] ) );
    pStruct->at = at2;
    ret2 = CopyBnsToAtom( pStruct, pBNS, pVA, pTCGroups, 1 );
    pStruct->at = at;
    if (ret2 < 0)
    {
        ret = ret2;
        goto exit_function;
    }
    /* (+) */
    pEdgePlusSuper = NULL;
    pvPlusSuper = NULL;
    if (( k = pTCGroups->nGroup[TCG_Plus] ) >= 0 &&
        ( ePlusSuper = pTCGroups->pTCG[k].nForwardEdge ) > 0 &&
        ( vPlusSuper = pTCGroups->pTCG[k].nVertexNumber ) >= num_at)
    {
        pEdgePlusSuper = pBNS->edge + ePlusSuper;
        pvPlusSuper = pBNS->vert + vPlusSuper;
    }
    pEdgePlusCarbons = NULL;
    pvPlusCarbons = NULL;
    if (( k = pTCGroups->nGroup[TCG_Plus_C0] ) > 0 &&
        ( ePlusCarbons = pTCGroups->pTCG[k].nForwardEdge ) > 0 &&
        ( vPlusCarbons = pTCGroups->pTCG[k].nVertexNumber ) >= num_at)
    {
        pEdgePlusCarbons = pBNS->edge + ePlusCarbons;
        pvPlusCarbons = pBNS->vert + vPlusCarbons;
    }
    pEdgePlusHeteroat = NULL;
    pvPlusHeteroat = NULL;
    if (( k = pTCGroups->nGroup[TCG_Plus0] ) > 0 &&
        ( ePlusHeteroat = pTCGroups->pTCG[k].nForwardEdge ) > 0 &&
        ( vPlusHeteroat = pTCGroups->pTCG[k].nVertexNumber ) >= num_at)
    {
        pEdgePlusHeteroat = pBNS->edge + ePlusHeteroat;
        pvPlusHeteroat = pBNS->vert + vPlusHeteroat;
    }
    pEdgePlusMetals = NULL;
    pvPlusMetals = NULL;
    if (( k = pTCGroups->nGroup[TCG_Plus_M0] ) > 0 &&
        ( ePlusMetals = pTCGroups->pTCG[k].nForwardEdge ) > 0 &&
        ( vPlusMetals = pTCGroups->pTCG[k].nVertexNumber ) >= num_at)
    {
        pEdgePlusMetals = pBNS->edge + ePlusMetals;
        pvPlusMetals = pBNS->vert + vPlusMetals;
    }
    /* (-) */
    pEdgeMinusSuper = NULL;
    pvMinusSuper = NULL;
    if (( k = pTCGroups->nGroup[TCG_Minus] ) >= 0 &&
        ( eMinusSuper = pTCGroups->pTCG[k].nForwardEdge ) > 0 &&
        ( vMinusSuper = pTCGroups->pTCG[k].nVertexNumber ) >= num_at)
    {
        pEdgeMinusSuper = pBNS->edge + eMinusSuper;
        pvMinusSuper = pBNS->vert + vMinusSuper;
    }
    pEdgeMinusCarbons = NULL;
    pvMinusCarbons = NULL;
    if (( k = pTCGroups->nGroup[TCG_Minus_C0] ) > 0 &&
        ( eMinusCarbons = pTCGroups->pTCG[k].nForwardEdge ) > 0 &&
        ( vMinusCarbons = pTCGroups->pTCG[k].nVertexNumber ) >= num_at)
    {
        pEdgeMinusCarbons = pBNS->edge + eMinusCarbons;
        pvMinusCarbons = pBNS->vert + vMinusCarbons;
    }
    pEdgeMinusHeteroat = NULL;
    pvMinusHeteroat = NULL;
    pEdgeMinusHeteroToSuper = NULL;
    if (( k = pTCGroups->nGroup[TCG_Minus0] ) > 0 &&
        ( eMinusHeteroat = pTCGroups->pTCG[k].nForwardEdge ) > 0 &&
        ( vMinusHeteroat = pTCGroups->pTCG[k].nVertexNumber ) >= num_at)
    {
        BNS_VERTEX *pvYMinusHetero;
        BNS_EDGE   *pe;
        int         vYMinusHetero;
        pEdgeMinusHeteroat = pBNS->edge + eMinusHeteroat;
        pvMinusHeteroat = pBNS->vert + vMinusHeteroat;
        /* next edge toward (-)super */
        if (pvMinusSuper)
        {
            vYMinusHetero = pEdgeMinusHeteroat->neighbor12 ^ vMinusHeteroat;
            pvYMinusHetero = pBNS->vert + vYMinusHetero;
            for (i = 0; i < pvYMinusHetero->num_adj_edges; i++)
            {
                pe = pBNS->edge + pvYMinusHetero->iedge[i];
                if (( pe->neighbor12 ^ vYMinusHetero ) == vMinusSuper)
                {
                    pEdgeMinusHeteroToSuper = pe;
                    eMinusHeteroToSuper = pe - pBNS->edge;
                    break;
                }
            }
        }
    }
    pEdgeMinusMetals = NULL;
    pvMinusMetals = NULL;
    if (( k = pTCGroups->nGroup[TCG_Minus_M0] ) > 0 &&
        ( eMinusMetals = pTCGroups->pTCG[k].nForwardEdge ) > 0 &&
        ( vMinusMetals = pTCGroups->pTCG[k].nVertexNumber ) >= num_at)
    {
        pEdgeMinusMetals = pBNS->edge + eMinusMetals;
        pvMinusMetals = pBNS->vert + vMinusMetals;
    }
    /* (+/-) */
    pvPlMn = NULL;
    if (pEdgePlusSuper)
    {
        vPlMn = pEdgePlusSuper->neighbor12 ^ vPlusSuper;
        pvPlMn = pBNS->vert + vPlMn;
    }
    else
        if (pEdgeMinusSuper)
        {
            vPlMn = pEdgeMinusSuper->neighbor12 ^ vMinusSuper;
            pvPlMn = pBNS->vert + vPlMn;
        }
    num_pos = num_neg = 0;
    /***************************************************************/
    /* Positive Charges                                            */
    /***************************************************************/
    if (pEdgePlusHeteroat && pEdgePlusMetals)
    {
        /* count charges */
        for (i = 0; i < num_at; i++)
        {
            if (!at2[i].radical &&
                  at2[i].charge > 0 &&
                  ( k = pVA[i].nCPlusGroupEdge - 1 ) >= 0)
            {
                v1 = pBNS->edge[k].neighbor1;
                v2 = pBNS->edge[k].neighbor1 ^ pBNS->edge[k].neighbor12;
                if (v1 == vPlusHeteroat || v2 == vPlusHeteroat)
                {
                    num_pos++;
                }
            }
        }
        /* attempt to move (+) from heteroatoms to metal atoms */
        num_min = inchi_min( num_pos, pEdgePlusHeteroat->flow );

        nDeltaPlus1 = pvPlusSuper->st_edge.cap - pvPlusSuper->st_edge.flow;
        nDeltaMinus1 = pvPlMn->st_edge.cap - pvPlMn->st_edge.flow;
        if (num_min && !nDeltaPlus1 && !nDeltaMinus1)
        {
            if (pEdgePlusSuper)
            {
                pEdgePlusSuper->forbidden |= forbidden_edge_mask;
            }
            if (pEdgeMinusSuper)
            {
                pEdgeMinusSuper->forbidden |= forbidden_edge_mask;
            }
            if (pEdgePlusCarbons)
            {
                pEdgePlusCarbons->forbidden |= forbidden_edge_mask;
            }
            if (pEdgeMinusCarbons)
            {
                pEdgeMinusCarbons->forbidden |= forbidden_edge_mask;
            }
            if (pEdgePlusHeteroat)
            {
                pEdgePlusHeteroat->forbidden |= forbidden_edge_mask;
            }
            if (pEdgeMinusHeteroat)
            {
                pEdgeMinusHeteroat->forbidden |= forbidden_edge_mask;
            }
            delta = 1;
            for (i = 0; i < num_min; i += delta)
            {
                v1 = pEdgePlusHeteroat->neighbor1;
                v2 = pEdgePlusHeteroat->neighbor12 ^ v1;
                pEdgePlusHeteroat->flow -= delta;
                pBNS->vert[v1].st_edge.flow -= delta;
                pBNS->vert[v2].st_edge.flow -= delta;
                pBNS->tot_st_flow -= 2 * delta;
                /* test for charhe cancellation */
                ret = RunBnsTestOnce( pBNS, pBD, pVA, &vPathStart, &vPathEnd, &nPathLen,
                                      &nDeltaH, &nDeltaCharge, &nNumVisitedAtoms );
                if (ret < 0)
                {
                    goto exit_function;
                }
                if (ret == 1 && ( vPathEnd == v1 && vPathStart == v2 ||
                    vPathEnd == v2 && vPathStart == v1 ) && nDeltaCharge == 0)
                {
                    ret = RunBnsRestoreOnce( pBNS, pBD, pVA, pTCGroups );
                    ( *pnNumRunBNS )++;
                    if (ret < 0)
                    {
                        goto exit_function;
                    }
                    else
                        if (ret == 1)
                        {
                            *pnTotalDelta += ret;
                        }
                        else
                        {
                            ret = RI_ERR_PROGR;
                            goto exit_function;
                        }
                }
                else
                {
                    pEdgePlusHeteroat->flow += delta;
                    pBNS->vert[v1].st_edge.flow += delta;
                    pBNS->vert[v2].st_edge.flow += delta;
                    pBNS->tot_st_flow += 2 * delta;
                    break;
                }
            }
            if (pEdgePlusSuper)
            {
                pEdgePlusSuper->forbidden &= inv_forbidden_edge_mask;
            }
            if (pEdgeMinusSuper)
            {
                pEdgeMinusSuper->forbidden &= inv_forbidden_edge_mask;
            }
            if (pEdgePlusCarbons)
            {
                pEdgePlusCarbons->forbidden &= inv_forbidden_edge_mask;
            }
            if (pEdgeMinusCarbons)
            {
                pEdgeMinusCarbons->forbidden &= inv_forbidden_edge_mask;
            }
            if (pEdgePlusHeteroat)
            {
                pEdgePlusHeteroat->forbidden &= inv_forbidden_edge_mask;
            }
            if (pEdgeMinusHeteroat)
            {
                pEdgeMinusHeteroat->forbidden &= inv_forbidden_edge_mask;
            }
        }
    }
    /***************************************************************/
    /* Negative Charges                                            */
    /***************************************************************/
    if (pEdgeMinusHeteroToSuper && pEdgeMinusMetals)
    {
        /* count charges */
        for (i = 0; i < num_at; i++)
        {
            if (!at2[i].radical &&
                  at2[i].charge < 0 &&
                  ( k = pVA[i].nCMinusGroupEdge - 1 ) >= 0)
            {
                v1 = pBNS->edge[k].neighbor1;
                v2 = pBNS->edge[k].neighbor1 ^ pBNS->edge[k].neighbor12;
                if (v1 == vMinusHeteroat || v2 == vMinusHeteroat)
                {
                    num_neg++;
                }
            }
        }
        if (num_neg)
        {
            /* attempt to move (+) from heteroatoms to metal atoms */
            num_min = inchi_min( num_neg, pEdgeMinusHeteroToSuper->flow );
        }

        nDeltaPlus1 = pvPlusSuper->st_edge.cap - pvPlusSuper->st_edge.flow;
        nDeltaMinus1 = pvPlMn->st_edge.cap - pvPlMn->st_edge.flow;
        if (num_min && !nDeltaPlus1 && !nDeltaMinus1)
        {
            if (pEdgePlusSuper)
            {
                pEdgePlusSuper->forbidden |= forbidden_edge_mask;
            }
            if (pEdgeMinusSuper)
            {
                pEdgeMinusSuper->forbidden |= forbidden_edge_mask;
            }
            if (pEdgePlusCarbons)
            {
                pEdgePlusCarbons->forbidden |= forbidden_edge_mask;
            }
            if (pEdgeMinusCarbons)
            {
                pEdgeMinusCarbons->forbidden |= forbidden_edge_mask;
            }
            if (pEdgePlusHeteroat)
            {
                pEdgePlusHeteroat->forbidden |= forbidden_edge_mask;
            }
            if (pEdgeMinusHeteroToSuper)
            {
                pEdgeMinusHeteroToSuper->forbidden |= forbidden_edge_mask;
            }
            delta = 1;
            for (i = 0; i < num_min; i += delta)
            {
                v1 = pEdgeMinusHeteroToSuper->neighbor1;
                v2 = pEdgeMinusHeteroToSuper->neighbor12 ^ v1;
                pEdgeMinusHeteroToSuper->flow -= delta;
                pBNS->vert[v1].st_edge.flow -= delta;
                pBNS->vert[v2].st_edge.flow -= delta;
                pBNS->tot_st_flow -= 2 * delta;
                /* test for charhe cancellation */
                ret = RunBnsTestOnce( pBNS, pBD, pVA, &vPathStart, &vPathEnd, &nPathLen,
                                      &nDeltaH, &nDeltaCharge, &nNumVisitedAtoms );
                if (ret < 0)
                {
                    goto exit_function;
                }
                if (ret == 1 && ( vPathEnd == v1 && vPathStart == v2 ||
                    vPathEnd == v2 && vPathStart == v1 ) && nDeltaCharge == 0)
                {
                    ret = RunBnsRestoreOnce( pBNS, pBD, pVA, pTCGroups );
                    ( *pnNumRunBNS )++;
                    if (ret < 0)
                    {
                        goto exit_function;
                    }
                    else
                    {
                        if (ret == 1)
                        {
                            *pnTotalDelta += ret;
                        }
                        else
                        {
                            ret = RI_ERR_PROGR;
                            goto exit_function;
                        }
                    }
                }
                else
                {
                    pEdgeMinusHeteroToSuper->flow += delta;
                    pBNS->vert[v1].st_edge.flow += delta;
                    pBNS->vert[v2].st_edge.flow += delta;
                    pBNS->tot_st_flow += 2 * delta;
                    break;
                }
            }
            if (pEdgePlusSuper)
            {
                pEdgePlusSuper->forbidden &= inv_forbidden_edge_mask;
            }
            if (pEdgeMinusSuper)
            {
                pEdgeMinusSuper->forbidden &= inv_forbidden_edge_mask;
            }
            if (pEdgePlusCarbons)
            {
                pEdgePlusCarbons->forbidden &= inv_forbidden_edge_mask;
            }
            if (pEdgeMinusCarbons)
            {
                pEdgeMinusCarbons->forbidden &= inv_forbidden_edge_mask;
            }
            if (pEdgePlusHeteroat)
            {
                pEdgePlusHeteroat->forbidden &= inv_forbidden_edge_mask;
            }
            if (pEdgeMinusHeteroToSuper)
            {
                pEdgeMinusHeteroToSuper->forbidden &= inv_forbidden_edge_mask;
            }
        }
    }
exit_function:
    return ret;
}
#endif


/****************************************************************************/
int RestoreCyanoGroup( BN_STRUCT *pBNS,
                       BN_DATA *pBD,
                       StrFromINChI *pStruct,
                       inp_ATOM *at,
                       inp_ATOM *at2,
                       VAL_AT *pVA,
                       ALL_TC_GROUPS *pTCGroups,
                       int *pnNumRunBNS,
                       int *pnTotalDelta,
                       int forbidden_edge_mask )
{
    Vertex     vPathStart, vPathEnd;
    int        nPathLen, nDeltaH, nDeltaCharge, nNumVisitedAtoms;
    BNS_EDGE  *pe;

    int i, j, ret2, ret;
    int num_at = pStruct->num_atoms;
    int num_deleted_H = pStruct->num_deleted_H;
    int len_at = num_at + num_deleted_H;
    int inv_forbidden_edge_mask = ~forbidden_edge_mask;
    Vertex v1, v2;

    EDGE_LIST CarbonChargeEdges;

    ret = 0;
    AllocEdgeList( &CarbonChargeEdges, EDGE_LIST_CLEAR );

    memcpy(at2, at, len_at * sizeof(at2[0]));
    pStruct->at = at2;
    ret2 = CopyBnsToAtom( pStruct, pBNS, pVA, pTCGroups, 1 );
    pStruct->at = at;
    if (ret2 < 0)
    {
        ret = ret2;
        goto exit_function;
    }

    for (i = 0; i < num_at && 0 <= ret; i++)
    {
        if (at2[i].valence == 1 &&
             at2[i].num_H == 0 &&
             at2[i].chem_bonds_valence == 2 &&
             at2[i].charge == -1 &&
             at2[i].radical == 0 &&
             pVA[i].cNumValenceElectrons == 5 &&  /* terminal N(-)=, P, As, Sb, Bi */
             pVA[i].nCMinusGroupEdge > 0 &&
             pVA[i].nTautGroupEdge == 0 &&
             at2[j = at2[i].neighbor[0]].valence == 2 &&
             at2[j].num_H == 0 &&
             at2[j].chem_bonds_valence == 4 &&
             at2[j].charge == 0 &&
             at2[j].radical == 0 &&
             pVA[j].cNumValenceElectrons == 4 && /* C or Si or Ge or Sn or Pb */
             pVA[i].cnListIndex > 0 &&
             cnList[pVA[i].cnListIndex - 1].bits == cn_bits_MN)
        {
            /* found N(-)=C= */
            pe = pBNS->edge + ( (long long)pVA[i].nCMinusGroupEdge - 1 ); /* N#N(+) triple bond edge */ /* djb-rwth: cast operator added */

            if (!pe->flow)
            {
                continue; /* wrong atom ??? Strange... */
            }
            v1 = pe->neighbor1;
            v2 = pe->neighbor12 ^ v1;
            pe->flow--;
            pBNS->vert[v1].st_edge.flow--;
            pBNS->vert[v2].st_edge.flow--;
            pBNS->tot_st_flow -= 2;
            pe->forbidden |= forbidden_edge_mask;

            /* do not let carbon atoms get charged */
            if (0 > ( ret = ForbidCarbonChargeEdges( pBNS, pTCGroups, &CarbonChargeEdges, forbidden_edge_mask ) ))
            {
                goto exit_function;
            }

            ret = RunBnsTestOnce( pBNS, pBD, pVA, &vPathStart, &vPathEnd, &nPathLen,
                                  &nDeltaH, &nDeltaCharge, &nNumVisitedAtoms );

            if (ret == 1 && ( (vPathEnd == v1 && vPathStart == v2) ||
                (vPathEnd == v2 && vPathStart == v1) ) && nDeltaCharge == 1) /* djb-rwth: addressing LLVM warnings */
            {
                ret = RunBnsRestoreOnce( pBNS, pBD, pVA, pTCGroups );
                ( *pnNumRunBNS )++;
                *pnTotalDelta += ret;
            }
            else
            {
                pe->flow++;
                pBNS->vert[v1].st_edge.flow++;
                pBNS->vert[v2].st_edge.flow++;
                pBNS->tot_st_flow += 2;
            }
            RemoveForbiddenEdgeMask( pBNS, &CarbonChargeEdges, forbidden_edge_mask );

            pe->forbidden &= inv_forbidden_edge_mask; /* unmask the edges */
        }
    }

exit_function:

    AllocEdgeList( &CarbonChargeEdges, EDGE_LIST_FREE );

    return ret;
}


/****************************************************************************/
int RestoreIsoCyanoGroup( BN_STRUCT *pBNS,
                          BN_DATA *pBD,
                          StrFromINChI *pStruct,
                          inp_ATOM *at,
                          inp_ATOM *at2,
                          VAL_AT *pVA,
                          ALL_TC_GROUPS *pTCGroups,
                          int *pnNumRunBNS,
                          int *pnTotalDelta,
                          int forbidden_edge_mask )
{
#define INC_EDGE_LIST 16
    Vertex     vPathStart, vPathEnd;
    int        nPathLen, nDeltaH, nDeltaCharge, nNumVisitedAtoms, num_failed, num_success;
    BNS_EDGE  *pe;
    Vertex    v1, v2;

    int i, j, ret2, ret, bIsCarbon;
    int num_at = pStruct->num_atoms;
    int num_deleted_H = pStruct->num_deleted_H;
    int len_at = num_at + num_deleted_H;
    int inv_forbidden_edge_mask = ~forbidden_edge_mask;
    EdgeIndex eNMinusEdge, eNPlusEdge, eNPlusEdge1, eN34Edge;
    EdgeIndex eNFlowerEdge1;

    EDGE_LIST CarbonChargeEdges, AllChargeEdges, IsoCyanoCarbonChargeEdges;

    ret = 0;
    num_failed = num_success = 0;
    AllocEdgeList( &CarbonChargeEdges, EDGE_LIST_CLEAR ); /* carbon charge edges */
    AllocEdgeList( &AllChargeEdges, EDGE_LIST_CLEAR );    /* heteroatom charge edges */
    AllocEdgeList( &IsoCyanoCarbonChargeEdges, EDGE_LIST_CLEAR );   /* C in C(+)#N(+) charge edges */

    memcpy(at2, at, len_at * sizeof(at2[0]));
    pStruct->at = at2;
    ret2 = CopyBnsToAtom( pStruct, pBNS, pVA, pTCGroups, 1 );
    pStruct->at = at;
    if (ret2 < 0)
    {
        ret = ret2;
        goto exit_function;
    }
    /* 1st attempt: take care of C(+)#N(+)-  => C(-)#N(+)- and remove 2 negative charges */
    /* This would produce nDeltaCharge = 2 */
    AllocEdgeList( &CarbonChargeEdges, 2 * num_at );
    for (i = 0; i < num_at && 0 <= ret; i++)
    {
        /* accumulate edges for subsequent fixing them */
        bIsCarbon = ( pVA[i].cNumValenceElectrons == 4 && pVA[i].cPeriodicRowNumber == 1 );
        /* djb-rwth: removing redundant variables/code */
        if (( eNMinusEdge = pVA[i].nCMinusGroupEdge - 1 ) >= 0 &&
             !pBNS->edge[eNMinusEdge].forbidden)
        {
            if (bIsCarbon)
            {
                if ((ret = AddToEdgeList( &CarbonChargeEdges, eNMinusEdge, INC_EDGE_LIST ))) /* djb-rwth: addressing LLVM warning */
                {
                    goto exit_function;
                }
            }
            else
            {
                if (!pVA[i].cMetal && !at2[i].endpoint && at2[i].charge != -1)
                {
                    if ((ret = AddToEdgeList( &AllChargeEdges, eNMinusEdge, INC_EDGE_LIST ))) /* djb-rwth: addressing LLVM warning */
                    {
                        goto exit_function;
                    }
                }
            }
        }
        if (( eNPlusEdge = pVA[i].nCPlusGroupEdge - 1 ) >= 0 &&
             !pBNS->edge[eNPlusEdge].forbidden)
        {
            if (bIsCarbon)
            {
                if ((ret = AddToEdgeList( &CarbonChargeEdges, eNPlusEdge, INC_EDGE_LIST ))) /* djb-rwth: addressing LLVM warning */
                {
                    goto exit_function;
                }
            }
            else
            {
                if (!pVA[i].cMetal && !at2[i].endpoint)
                {
                    if ((ret = AddToEdgeList( &AllChargeEdges, eNPlusEdge, INC_EDGE_LIST ))) /* djb-rwth: addressing LLVM warning */
                    {
                        goto exit_function;
                    }
                    if (pVA[i].cNumValenceElectrons == 5 &&
                         NO_VERTEX != ( eNFlowerEdge1 = GetChargeFlowerUpperEdge( pBNS, pVA, eNPlusEdge ) ) &&
                         !pBNS->edge[eNFlowerEdge1].flow)
                    {
                        if ((ret = AddToEdgeList( &AllChargeEdges, eNFlowerEdge1, INC_EDGE_LIST ))) /* djb-rwth: addressing LLVM warning */
                        {
                            goto exit_function;
                        }
                    }
                }
            }
        }
        if (bIsCarbon &&
             0 <= eNMinusEdge &&
             0 <= eNPlusEdge &&
             at2[i].valence == 1 &&
             at2[i].num_H == 0 &&
             at2[i].radical == 0 &&
             !pBNS->edge[eNMinusEdge].forbidden &&
             pBNS->edge[eNMinusEdge].flow == 0 &&
             !pBNS->edge[eNPlusEdge].forbidden &&
             pBNS->edge[eNPlusEdge].flow == 0 &&   /* found terminal C(+) */

             at2[j = at2[i].neighbor[0]].valence == 2 &&
             at2[j].num_H == 0 &&
             at2[j].radical == 0 &&
             pVA[j].cNumValenceElectrons == 5 &&
             ( eNPlusEdge1 = pVA[j].nCPlusGroupEdge - 1 ) >= 0 && 
             pBNS->edge[eNPlusEdge].flow == 0) /* djb-rwth: ignoring LLVM warning: variable used */
        {     /* -N(+)- */

#ifdef NEVER /* I have not found a good reason to do this yet */
            /* fix (+) charge on -N(+)- as much as C charges are fixed */
            if (ret = AddToEdgeList( &CarbonChargeEdges, eNPlusEdge1, INC_EDGE_LIST ))
            {
                goto exit_function;
            }
            /* fix floer edge to prevent N(V) ??? */
            if (NO_VERTEX != ( eNFlowerEdge1 = GetChargeFlowerUpperEdge( pBNS, pVA, eNPlusEdge1 ) ) &&
                 !pBNS->edge[eNFlowerEdge1].flow)
            {
                if (ret = AddToEdgeList( &CarbonChargeEdges, eNFlowerEdge1, INC_EDGE_LIST ))
                {
                    goto exit_function;
                }
            }
#endif
            /*
               Carbon(+)         Carbon(-)
               ChargeStruct:     ChargeStruct:

                         5(+C)             5(+C)
                        /                 //
               6(-C)  4          6(-C)  4
                   \ //             \\ /
                    3                 3
                    |                 |
                    2                 2
                    ||                ||
                   -C1-              -C1-
                    |                 |

             3-6 is (-) Charge Edge; 4-5 is (+) Charge Edge

             To convert the left pattern to the right one:

             We need to release these charge edges and decrement
             edge 3-4 flow to change charge from (+) to (-)

            */

            /* find vertices 4 and 5 */
            v1 = pBNS->edge[eNPlusEdge].neighbor1; /* one of two vertices incident with edge 4-5 */
            v2 = pBNS->edge[eNPlusEdge].neighbor12 ^ v1;
            if (IS_BNS_VT_C_GR( pBNS->vert[v1].type ))
            {
                /* v1 is 5(+C) */
                /* djb-rwth: removing redundant variables */
                v1 = v2;
                /* djb-rwth: removing redundant code */
            }
            /* v1 should be 4, v2 - 5(+C) */
            if (!IS_BNS_VT_CHRG_STRUCT( pBNS->vert[v1].type ) || pBNS->vert[v1].num_adj_edges != 2)
            {
                continue; /* mismatch */
            }
            /* find edge 3-4 */
            eN34Edge = pBNS->vert[v1].iedge[pBNS->vert[v1].iedge[0] == eNPlusEdge];
            if (pBNS->edge[eN34Edge].forbidden || !pBNS->edge[eN34Edge].flow)
            {
                continue;
            }
            /* save 3 edges: 6-3, 4-5, and 3-4 in this order */
            if ((ret = AddToEdgeList( &IsoCyanoCarbonChargeEdges, eNMinusEdge, INC_EDGE_LIST ))) /* djb-rwth: addressing LLVM warning */
            {
                goto exit_function;
            }
            if ((ret = AddToEdgeList( &IsoCyanoCarbonChargeEdges, eNPlusEdge, INC_EDGE_LIST ))) /* djb-rwth: addressing LLVM warning */
            {
                goto exit_function;
            }
            if ((ret = AddToEdgeList( &IsoCyanoCarbonChargeEdges, eN34Edge, INC_EDGE_LIST ))) /* djb-rwth: addressing LLVM warning */
            {
                goto exit_function;
            }
        }
    }
    /* 1st attempt: move (-) charges from heteroatoms to C(+) */
    SetForbiddenEdgeMask( pBNS, &CarbonChargeEdges, forbidden_edge_mask );
    SetForbiddenEdgeMask( pBNS, &AllChargeEdges, forbidden_edge_mask );
    RemoveForbiddenEdgeMask( pBNS, &IsoCyanoCarbonChargeEdges, forbidden_edge_mask );
    for (i = IsoCyanoCarbonChargeEdges.num_edges - 3; 0 <= i; i -= 3)
    {
        /* djb-rwth: removing redundant code */
        eN34Edge = IsoCyanoCarbonChargeEdges.pnEdges[i + 2];

        pe = pBNS->edge + eN34Edge;
        pe->forbidden |= forbidden_edge_mask;
        if (!pe->flow)
        {
            continue; /* already done */
        }

        v1 = pe->neighbor1;
        v2 = pe->neighbor12 ^ v1;
        pe->flow--;
        pBNS->vert[v1].st_edge.flow--;
        pBNS->vert[v2].st_edge.flow--;
        pBNS->tot_st_flow -= 2;

        ret = RunBnsTestOnce( pBNS, pBD, pVA, &vPathStart, &vPathEnd, &nPathLen,
                              &nDeltaH, &nDeltaCharge, &nNumVisitedAtoms );

        if (ret == 1 && ( (vPathEnd == v1 && vPathStart == v2) ||
            (vPathEnd == v2 && vPathStart == v1) ) && nDeltaCharge <= -2) /* djb-rwth: addressing LLVM warnings */
        {
            ret = RunBnsRestoreOnce( pBNS, pBD, pVA, pTCGroups );
            ( *pnNumRunBNS )++;
            *pnTotalDelta += ret;
            num_success++;
        }
        else
        {
            pe->flow++;
            pBNS->vert[v1].st_edge.flow++;
            pBNS->vert[v2].st_edge.flow++;
            pBNS->tot_st_flow += 2;
            pe->forbidden &= inv_forbidden_edge_mask;
            num_failed++;
        }
    }
    if (num_failed)
    {
        /* relax conditions: allow all heteroatoms to change charge */
        RemoveForbiddenEdgeMask( pBNS, &AllChargeEdges, forbidden_edge_mask );
        for (i = IsoCyanoCarbonChargeEdges.num_edges - 3; 0 <= i; i -= 3)
        {
            /* djb-rwth: removing redundant code */
            eN34Edge = IsoCyanoCarbonChargeEdges.pnEdges[i + 2];

            pe = pBNS->edge + eN34Edge;
            pe->forbidden |= forbidden_edge_mask;
            if (!pe->flow)
            {
                continue; /* already done */
            }

            v1 = pe->neighbor1;
            v2 = pe->neighbor12 ^ v1;
            pe->flow--;
            pBNS->vert[v1].st_edge.flow--;
            pBNS->vert[v2].st_edge.flow--;
            pBNS->tot_st_flow -= 2;

            ret = RunBnsTestOnce( pBNS, pBD, pVA, &vPathStart, &vPathEnd, &nPathLen,
                                  &nDeltaH, &nDeltaCharge, &nNumVisitedAtoms );

            if (ret == 1 && ( (vPathEnd == v1 && vPathStart == v2) ||
                (vPathEnd == v2 && vPathStart == v1) ) && nDeltaCharge <= 2) /* djb-rwth: addressing LLVM warnings */
            {
                ret = RunBnsRestoreOnce( pBNS, pBD, pVA, pTCGroups );
                ( *pnNumRunBNS )++;
                *pnTotalDelta += ret;
                num_success++;
            }
            else
            {
                pe->flow++;
                pBNS->vert[v1].st_edge.flow++;
                pBNS->vert[v2].st_edge.flow++;
                pBNS->tot_st_flow += 2;
                pe->forbidden &= inv_forbidden_edge_mask; /* let it change if it wants */
                num_failed++;
            }
        }
    }
    RemoveForbiddenEdgeMask( pBNS, &CarbonChargeEdges, forbidden_edge_mask );
    RemoveForbiddenEdgeMask( pBNS, &AllChargeEdges, forbidden_edge_mask );
    RemoveForbiddenEdgeMask( pBNS, &IsoCyanoCarbonChargeEdges, forbidden_edge_mask );


exit_function:

    AllocEdgeList( &CarbonChargeEdges, EDGE_LIST_FREE );
    AllocEdgeList( &AllChargeEdges, EDGE_LIST_FREE );
    AllocEdgeList( &IsoCyanoCarbonChargeEdges, EDGE_LIST_FREE );

    return ret;
#undef INC_EDGE_LIST
}


/****************************************************************************/
int FixMetal_Nminus_Ominus( BN_STRUCT *pBNS,
                            BN_DATA *pBD,
                            StrFromINChI *pStruct,
                            inp_ATOM *at,
                            inp_ATOM *at2,
                            VAL_AT *pVA,
                            ALL_TC_GROUPS *pTCGroups,
                            int *pnNumRunBNS,
                            int *pnTotalDelta,
                            int forbidden_edge_mask )
{
#define INC_EDGE_LIST 16
    Vertex     vPathStart, vPathEnd;
    int        nPathLen, nDeltaH, nDeltaCharge, nNumVisitedAtoms;
    int        num_success, n; /* djb-rwth: removing redundant variables */
    BNS_EDGE  *pe;
    Vertex    v1, v2;

    int i, j, k, ret2, ret;
    int num_at = pStruct->num_atoms;
    int num_deleted_H = pStruct->num_deleted_H;
    int len_at = num_at + num_deleted_H;
    int inv_forbidden_edge_mask = ~forbidden_edge_mask;
    EdgeIndex e, eNMinusEdge, eNMinusEdge1, eNMinusEdge2, eNPlusEdge2;

    EDGE_LIST AllChargeEdges;

    ret = 0;
    num_success = 0; /* djb-rwth: removing redundant code */
    AllocEdgeList( &AllChargeEdges, EDGE_LIST_CLEAR );

    memcpy(at2, at, len_at * sizeof(at2[0]));
    pStruct->at = at2;
    ret2 = CopyBnsToAtom( pStruct, pBNS, pVA, pTCGroups, 1 );
    pStruct->at = at;
    if (ret2 < 0)
    {
        ret = ret2;
        goto exit_function;
    }
    /* attepmt #1 N#N(+)-N => N(-)=N(+)=N */
    for (i = 0; i < num_at && 0 <= ret; i++)
    {
        if (at2[i].valence == 1 &&
             at2[i].num_H == 0 &&
             at2[i].radical == 0 &&
             pVA[i].cNumValenceElectrons == 6 &&  /* terminal -O */
             ( eNMinusEdge = pVA[i].nCMinusGroupEdge - 1 ) >= 0 && pBNS->edge[eNMinusEdge].flow == 1 &&
             !pBNS->edge[eNMinusEdge].forbidden && /* terminal O(-) */

             at2[j = at2[i].neighbor[0]].valence == 2 &&
             at2[j].num_H == 0 &&
             at2[j].radical == 0 &&
             pVA[j].cNumValenceElectrons == 5 &&
             ( eNMinusEdge1 = pVA[j].nCMinusGroupEdge - 1 ) >= 0 && pBNS->edge[eNMinusEdge1].flow == 1 &&
             !pBNS->edge[eNMinusEdge1].forbidden &&

             pVA[k = at2[j].neighbor[at2[j].neighbor[0] == i]].cMetal &&

             ( eNMinusEdge2 = pVA[k].nCMinusGroupEdge - 1 ) >= 0 &&
             !pBNS->edge[eNMinusEdge2].forbidden &&
             ( eNPlusEdge2 = pVA[k].nCPlusGroupEdge - 1 ) >= 0 &&
             !pBNS->edge[eNPlusEdge2].forbidden)
        {
            /* found M(q)-N(-)-O(-); convert to M(q-2)-N=O */

            /* find all charge edges to fix */
            if (0 == AllChargeEdges.num_edges)
            {
                for (n = 0; n < num_at; n++)
                {
                    if (( e = pVA[n].nCMinusGroupEdge - 1 ) >= 0 &&
                         !pBNS->edge[e].forbidden)
                    {
                        if ((ret = AddToEdgeList( &AllChargeEdges, e, num_at ))) /* djb-rwth: addressing LLVM warning */
                        {
                            goto exit_function;
                        }
                    }
                    if (( e = pVA[n].nCPlusGroupEdge - 1 ) >= 0 &&
                         !pBNS->edge[e].forbidden)
                    {
                        if ((ret = AddToEdgeList( &AllChargeEdges, e, num_at ))) /* djb-rwth: addressing LLVM warning */
                        {
                            goto exit_function;
                        }
                        if (pVA[n].cNumValenceElectrons == 6 &&
                             NO_VERTEX != ( e = GetChargeFlowerUpperEdge( pBNS, pVA, e ) ) &&
                             pBNS->edge[e].flow == 0)
                        {
                            if ((ret = AddToEdgeList( &AllChargeEdges, e, num_at ))) /* djb-rwth: addressing LLVM warning */
                            {
                                goto exit_function;
                            }
                        }
                    }
                }
            }

            /* djb-rwth: removing redundant code */
            /* djb-rwth: removing redundant code */

            SetForbiddenEdgeMask( pBNS, &AllChargeEdges, forbidden_edge_mask );
            pBNS->edge[eNMinusEdge1].forbidden &= inv_forbidden_edge_mask;
            pBNS->edge[eNMinusEdge2].forbidden &= inv_forbidden_edge_mask;
            pBNS->edge[eNPlusEdge2].forbidden &= inv_forbidden_edge_mask;

            pe = pBNS->edge + eNMinusEdge; /* must be already fixed as a charge edge */

            v1 = pe->neighbor1;
            v2 = pe->neighbor12 ^ v1;
            pe->flow--;
            pBNS->vert[v1].st_edge.flow--;
            pBNS->vert[v2].st_edge.flow--;
            pBNS->tot_st_flow -= 2;

            ret = RunBnsTestOnce( pBNS, pBD, pVA, &vPathStart, &vPathEnd, &nPathLen,
                                  &nDeltaH, &nDeltaCharge, &nNumVisitedAtoms );

            if (ret == 1 && ( (vPathEnd == v1 && vPathStart == v2) ||
                (vPathEnd == v2 && vPathStart == v1) ) /*&& nDeltaCharge == nDeltaChargeMax*/) /* djb-rwth: addressing LLVM warnings */
            { 
                ret = RunBnsRestoreOnce( pBNS, pBD, pVA, pTCGroups );
                ( *pnNumRunBNS )++;
                *pnTotalDelta += ret;
                num_success++;
            }
            else
            {
                pe->flow++;
                pBNS->vert[v1].st_edge.flow++;
                pBNS->vert[v2].st_edge.flow++;
                pBNS->tot_st_flow += 2;
                /* djb-rwth: removing redundant code */
            }
            RemoveForbiddenEdgeMask( pBNS, &AllChargeEdges, forbidden_edge_mask );
        }
    }
    ret = num_success;

exit_function:

    AllocEdgeList( &AllChargeEdges, EDGE_LIST_FREE );

    return ret;
#undef INC_EDGE_LIST
}


/****************************************************************************/
int RestoreNNNgroup( BN_STRUCT *pBNS,
                     BN_DATA *pBD,
                     StrFromINChI *pStruct,
                     inp_ATOM *at,
                     inp_ATOM *at2,
                     VAL_AT *pVA,
                     ALL_TC_GROUPS *pTCGroups,
                     int *pnNumRunBNS,
                     int *pnTotalDelta,
                     int forbidden_edge_mask )
{
#define INC_EDGE_LIST 16
    Vertex     vPathStart, vPathEnd;
    int        nPathLen, nDeltaH, nDeltaCharge, nNumVisitedAtoms, num_failed, num_success, n, nDeltaChargeMax;
    BNS_EDGE  *pe;
    Vertex    v1, v2;

    int i, j, k, ret2, ret;
    int num_at = pStruct->num_atoms;
    int num_deleted_H = pStruct->num_deleted_H;
    int len_at = num_at + num_deleted_H;
    int inv_forbidden_edge_mask = ~forbidden_edge_mask;
    EdgeIndex eNMinusEdge, eNPlusEdge, eNMinusEdge1, eNPlusEdge1, eNMinusEdge2, eNPlusEdge2;
    EdgeIndex eNFlowerEdge1, eNFlowerEdge2;

    EDGE_LIST CarbonChargeEdges, AllChargeEdges, NNNChargeEdges, CurNNNChargeEdges, AllNNNTermAtoms, AllNIIIChargeEdges;

    ret = 0;
    num_failed = num_success = 0;
    AllocEdgeList( &CarbonChargeEdges, EDGE_LIST_CLEAR );
    AllocEdgeList( &AllChargeEdges, EDGE_LIST_CLEAR );
    AllocEdgeList( &NNNChargeEdges, EDGE_LIST_CLEAR );
    AllocEdgeList( &CurNNNChargeEdges, EDGE_LIST_CLEAR );
    AllocEdgeList( &AllNNNTermAtoms, EDGE_LIST_CLEAR );
    AllocEdgeList( &AllNIIIChargeEdges, EDGE_LIST_CLEAR );

    memcpy(at2, at, len_at * sizeof(at2[0]));
    pStruct->at = at2;
    ret2 = CopyBnsToAtom( pStruct, pBNS, pVA, pTCGroups, 1 );
    pStruct->at = at;
    if (ret2 < 0)
    {
        ret = ret2;
        goto exit_function;
    }
    /* attepmt #1 N#N(+)-N => N(-)=N(+)=N: naive approach; expecting tp move (-) from some other atom */
    for (i = 0; i < num_at && 0 <= ret; i++)
    {
        if (at2[i].valence == 1 &&
             at2[i].num_H == 0 &&
             at2[i].chem_bonds_valence == 3 &&
             at2[i].charge == 0 &&
             at2[i].radical == 0 &&
             pVA[i].cNumValenceElectrons == 5 &&  /* terminal N# */
             ( eNMinusEdge = pVA[i].nCMinusGroupEdge - 1 ) >= 0 && pBNS->edge[eNMinusEdge].flow == 0 &&
             !pBNS->edge[eNMinusEdge].forbidden &&
             at2[j = at2[i].neighbor[0]].valence == 2 &&
             at2[j].num_H == 0 &&
             at2[j].chem_bonds_valence == 4 &&
             at2[j].charge == 1 &&
             at2[j].radical == 0 &&
             pVA[j].cNumValenceElectrons == 5 &&
             ( eNPlusEdge = pVA[j].nCPlusGroupEdge - 1 ) >= 0 && pBNS->edge[eNPlusEdge].flow == 0 &&
             !pBNS->edge[eNPlusEdge].forbidden &&
             at2[k = at2[j].neighbor[at2[j].neighbor[0] == i]].valence == 2 &&
             at2[k].num_H == 0 &&
             at2[k].chem_bonds_valence == 3 &&
             pVA[k].cNumValenceElectrons == 5 &&
             ( eNPlusEdge2 = pVA[k].nCPlusGroupEdge - 1 ) >= 0 && pBNS->edge[eNPlusEdge2].flow == 1 &&
             !pBNS->edge[eNPlusEdge2].forbidden &&
             pVA[i].cnListIndex > 0 &&
             cnList[pVA[i].cnListIndex - 1].bits == cn_bits_MN)
        {
            /* found N#N(+)-N~ where the last N (at2[k]) may be charged */
            pe = pBNS->edge + pBNS->vert[i].iedge[0]; /* N#N(+) triple bond edge */

            v1 = pe->neighbor1;
            v2 = pe->neighbor12 ^ v1;
            pe->flow--;
            pBNS->vert[v1].st_edge.flow--;
            pBNS->vert[v2].st_edge.flow--;
            pBNS->tot_st_flow -= 2;

            pe->forbidden |= forbidden_edge_mask;
            pBNS->edge[eNPlusEdge].forbidden |= forbidden_edge_mask;
            pBNS->edge[eNPlusEdge2].forbidden |= forbidden_edge_mask;


            if (!CarbonChargeEdges.num_edges)
            {
                /* do not let carbon atoms get charged */
                AllocEdgeList( &CarbonChargeEdges, INC_EDGE_LIST );
                if (0 > ( ret = ForbidCarbonChargeEdges( pBNS, pTCGroups, &CarbonChargeEdges, forbidden_edge_mask ) ))
                {
                    goto exit_function;
                }
            }
            else
            {
                SetForbiddenEdgeMask( pBNS, &CarbonChargeEdges, forbidden_edge_mask );
            }
            ret = RunBnsTestOnce( pBNS, pBD, pVA, &vPathStart, &vPathEnd, &nPathLen,
                                  &nDeltaH, &nDeltaCharge, &nNumVisitedAtoms );

            if (ret == 1 && ( (vPathEnd == v1 && vPathStart == v2) ||
                (vPathEnd == v2 && vPathStart == v1) ) && nDeltaCharge <= 0) /* djb-rwth: addressing LLVM warnings */
            {
                ret = RunBnsRestoreOnce( pBNS, pBD, pVA, pTCGroups );
                ( *pnNumRunBNS )++;
                *pnTotalDelta += ret;
                num_success++;
                /* fix charges on N(-)=N(+)=N- */
                if ((ret = AddToEdgeList( &CarbonChargeEdges, eNMinusEdge, INC_EDGE_LIST ))) /* djb-rwth: addressing LLVM warning */
                {
                    goto exit_function;
                }
                if ((ret = AddToEdgeList( &CarbonChargeEdges, eNPlusEdge, INC_EDGE_LIST ))) /* djb-rwth: addressing LLVM warning */
                {
                    goto exit_function;
                }
            }
            else
            {
                pe->flow++;
                pBNS->vert[v1].st_edge.flow++;
                pBNS->vert[v2].st_edge.flow++;
                pBNS->tot_st_flow += 2;
                num_failed++;
            }
            RemoveForbiddenEdgeMask( pBNS, &CarbonChargeEdges, forbidden_edge_mask );

            pe->forbidden &= inv_forbidden_edge_mask;
            pBNS->edge[eNPlusEdge].forbidden &= inv_forbidden_edge_mask;
            pBNS->edge[eNPlusEdge2].forbidden &= inv_forbidden_edge_mask;
        }
    }

    /* 2nd attempt: take care of N#N(+)-N=-...=N-N(-) */
    /* This would produce nDeltaCharge >= 2 */

    AllChargeEdges.num_edges = 0;
    AllNNNTermAtoms.num_edges = 0;
    NNNChargeEdges.num_edges = 0;
    AllNIIIChargeEdges.num_edges = 0;

    for (i = 0; i < num_at && 0 <= ret; i++)
    {
        if (( eNMinusEdge = pVA[i].nCMinusGroupEdge - 1 ) >= 0 &&
             !pBNS->edge[eNMinusEdge].forbidden)
        {
            if ((ret = AddToEdgeList( &AllChargeEdges, eNMinusEdge, INC_EDGE_LIST ))) /* djb-rwth: addressing LLVM warning */
            {
                goto exit_function;
            }
        }
        else
        {
            eNMinusEdge = -1;
        }
        if (( eNPlusEdge = pVA[i].nCPlusGroupEdge - 1 ) >= 0 &&
             !pBNS->edge[eNPlusEdge].forbidden)
        {
            if ((ret = AddToEdgeList( &AllChargeEdges, eNPlusEdge, INC_EDGE_LIST ))) /* djb-rwth: addressing LLVM warning */
            {
                goto exit_function;
            }
            if (pVA[i].cNumValenceElectrons == 5 && at2[i].valence == 3 && at2[i].chem_bonds_valence == 3)
            {
                if ((ret = AddToEdgeList( &AllNIIIChargeEdges, eNPlusEdge, INC_EDGE_LIST ))) /* djb-rwth: addressing LLVM warning */
                {
                    goto exit_function;
                }
            }
            /* N flower edge */
            if (pVA[i].cNumValenceElectrons == 5 && pVA[i].cPeriodicRowNumber == 1 &&
                 NO_VERTEX != ( eNFlowerEdge1 = GetChargeFlowerUpperEdge( pBNS, pVA, eNPlusEdge ) ) &&
                 pBNS->edge[eNFlowerEdge1].flow == 0 &&
                 ( ret = AddToEdgeList( &AllChargeEdges, eNFlowerEdge1, INC_EDGE_LIST ) ))
            {
                goto exit_function;
            }
        }
        /* djb-rwth: removing redundant code */

        if (0 <= eNMinusEdge &&
             at2[i].valence == 1 &&
             at2[i].num_H == 0 &&
             at2[i].radical == 0 &&
             pVA[i].cNumValenceElectrons == 5 &&  /* terminal N# */

             at2[j = at2[i].neighbor[0]].valence == 2 &&
             at2[j].num_H == 0 &&
             at2[j].radical == 0 &&
             pVA[j].cNumValenceElectrons == 5 &&
             ( eNMinusEdge1 = pVA[j].nCMinusGroupEdge - 1 ) >= 0 &&
             ( eNPlusEdge1 = pVA[j].nCPlusGroupEdge - 1 ) >= 0 &&
             !pBNS->edge[eNMinusEdge1].forbidden &&
             !pBNS->edge[eNPlusEdge1].forbidden &&

             at2[k = at2[j].neighbor[at2[j].neighbor[0] == i]].valence == 2 &&
             at2[k].num_H == 0 &&
             at2[k].radical == 0 &&
             pVA[k].cNumValenceElectrons == 5 &&
             ( eNMinusEdge2 = pVA[k].nCMinusGroupEdge - 1 ) >= 0 &&
             ( eNPlusEdge2 = pVA[k].nCPlusGroupEdge - 1 ) >= 0 &&
             !pBNS->edge[eNMinusEdge2].forbidden &&
             !pBNS->edge[eNPlusEdge2].forbidden &&

             pVA[i].cnListIndex > 0 &&
             cnList[pVA[i].cnListIndex - 1].bits == cn_bits_MN)
        {
            /* found N#N(+)-N~ or N(-)=N-N= where the last N (at2[k]) may be charged */

            /* 1. N(-)=N(+)=N- */
            if (pBNS->edge[eNMinusEdge].flow == 1 &&  /* N(-) */
                 pBNS->edge[eNMinusEdge1].flow == 0 && pBNS->edge[eNPlusEdge1].flow == 0 && /* N(+) */
                 pBNS->edge[eNMinusEdge2].flow == 0 && pBNS->edge[eNPlusEdge2].flow == 1    /* N */)
            {
                continue; /* already good */
            }
            /* accumulate terminal atoms of all other NNN */
            if ((ret = AddToEdgeList( &AllNNNTermAtoms, i, INC_EDGE_LIST ))) /* djb-rwth: addressing LLVM warning */
            {
                goto exit_function;
            }
            /* 2. N#N(+)-N= */
            if (pBNS->edge[eNMinusEdge].flow == 0 && /* N */
                 pBNS->edge[eNMinusEdge1].flow == 0 && pBNS->edge[eNPlusEdge1].flow == 0 && /* N(+) */
                 pBNS->edge[eNMinusEdge2].flow == 0 && pBNS->edge[eNPlusEdge2].flow == 1    /* N */)
            {
/* unfix (-) edge on terminal N# */
                if ((ret = AddToEdgeList( &NNNChargeEdges, eNMinusEdge, INC_EDGE_LIST ))) /* djb-rwth: addressing LLVM warning */
                {
                    goto exit_function;
                }
                continue;
            }
            /* 3. N(-)=N-N= */
            if (pBNS->edge[eNMinusEdge].flow == 1 && /* N(-) */
                 pBNS->edge[eNMinusEdge1].flow == 0 && pBNS->edge[eNPlusEdge1].flow == 1 && /* N */
                 pBNS->edge[eNMinusEdge2].flow == 0 && pBNS->edge[eNPlusEdge2].flow == 1    /* N */)
            {
                /* unfix (+) edge on middle N */
                if ((ret = AddToEdgeList( &NNNChargeEdges, eNPlusEdge1, INC_EDGE_LIST ))) /* djb-rwth: addressing LLVM warning */
                {
                    goto exit_function;
                }
                continue;
            }
            /* 4. N#N(+)-N(-)- */
            if (pBNS->edge[eNMinusEdge].flow == 0 &&  /* N */
                 pBNS->edge[eNMinusEdge1].flow == 0 && pBNS->edge[eNPlusEdge1].flow == 0 && /* N(+) */
                 pBNS->edge[eNMinusEdge2].flow == 1 && pBNS->edge[eNPlusEdge2].flow == 1    /* N(-) */)
            {
                /* unfix (-) edge on the 1st and 3rd N */
                if ((ret = AddToEdgeList( &NNNChargeEdges, eNMinusEdge, INC_EDGE_LIST ))) /* djb-rwth: addressing LLVM warning */
                {
                    goto exit_function;
                }
                if ((ret = AddToEdgeList( &NNNChargeEdges, eNMinusEdge2, INC_EDGE_LIST ))) /* djb-rwth: addressing LLVM warning */
                {
                    goto exit_function;
                }
                continue;
            }
            /* 5. N#N(+)-N(+)# */
            if (pBNS->edge[eNMinusEdge].flow == 0 &&  /* N */
                 pBNS->edge[eNMinusEdge1].flow == 0 && pBNS->edge[eNPlusEdge1].flow == 0 && /* N(+) */
                 pBNS->edge[eNMinusEdge2].flow == 0 && pBNS->edge[eNPlusEdge2].flow == 0    /* N(+) */)
            {
                /* unfix (-) edge on the 1st and (+) edge on the 3rd N */
                if ((ret = AddToEdgeList( &NNNChargeEdges, eNMinusEdge, INC_EDGE_LIST ))) /* djb-rwth: addressing LLVM warning */
                {
                    goto exit_function;
                }
                if ((ret = AddToEdgeList( &NNNChargeEdges, eNPlusEdge2, INC_EDGE_LIST ))) /* djb-rwth: addressing LLVM warning */
                {
                    goto exit_function;
                }
                continue;
            }
        }
    }
    /* try to fix each NNN */
    for (n = AllNNNTermAtoms.num_edges - 1; 0 <= n; n--)
    {
        i = AllNNNTermAtoms.pnEdges[n];
        eNMinusEdge = pVA[i].nCMinusGroupEdge - 1;
        /*eNPlusEdge = pVA[i].nCPlusGroupEdge - 1;*/
        j = at2[i].neighbor[0];
        eNMinusEdge1 = pVA[j].nCMinusGroupEdge - 1;
        eNPlusEdge1 = pVA[j].nCPlusGroupEdge - 1;
        k = at2[j].neighbor[at2[j].neighbor[0] == i];
        eNMinusEdge2 = pVA[k].nCMinusGroupEdge - 1;
        eNPlusEdge2 = pVA[k].nCPlusGroupEdge - 1;
        /*SetForbiddenEdgeMask( pBNS, &CarbonChargeEdges, forbidden_edge_mask );*/
        /* 1. N(-)=N(+)=N- */
        if (pBNS->edge[eNMinusEdge].flow == 1 &&  /* N(-) */
             pBNS->edge[eNMinusEdge1].flow == 0 && pBNS->edge[eNPlusEdge1].flow == 0 && /* N(+) */
             pBNS->edge[eNMinusEdge2].flow == 0 && pBNS->edge[eNPlusEdge2].flow == 1    /* N */)
        {

            RemoveFromEdgeListByValue( &NNNChargeEdges, eNMinusEdge );
            RemoveFromEdgeListByValue( &NNNChargeEdges, eNMinusEdge1 );
            RemoveFromEdgeListByValue( &NNNChargeEdges, eNPlusEdge1 );
            RemoveFromEdgeListByValue( &NNNChargeEdges, eNMinusEdge2 );
            RemoveFromEdgeListByValue( &NNNChargeEdges, eNPlusEdge2 );

            pe = NULL;
        }

        else
        {
            /* 2. N#N(+)-N= */
            if (pBNS->edge[eNMinusEdge].flow == 0 &&  /* N */
                 pBNS->edge[eNMinusEdge1].flow == 0 && pBNS->edge[eNPlusEdge1].flow == 0 && /* N(+) */
                 pBNS->edge[eNMinusEdge2].flow == 0 && pBNS->edge[eNPlusEdge2].flow == 1    /* N */)
            {
                /* decrement triple bond on terminal N# */
                pe = pBNS->edge + pBNS->vert[i].iedge[0];
            }
            else
            {
                /* 3. N(-)=N-N= */
                if (pBNS->edge[eNMinusEdge].flow == 1 &&  /* N(-) */
                     pBNS->edge[eNMinusEdge1].flow == 0 && pBNS->edge[eNPlusEdge1].flow == 1 && /* N */
                     pBNS->edge[eNMinusEdge2].flow == 0 && pBNS->edge[eNPlusEdge2].flow == 1    /* N */)
                {
                    /* decrement flow on (+) charge edge of the middle =N- */
                    pe = pBNS->edge + eNPlusEdge1;
                }
                else
                {
                    /* 4. N#N(+)-N(-)- */
                    if (pBNS->edge[eNMinusEdge].flow == 0 &&  /* N */
                         pBNS->edge[eNMinusEdge1].flow == 0 && pBNS->edge[eNPlusEdge1].flow == 0 && /* N(+) */
                         pBNS->edge[eNMinusEdge2].flow == 1 && pBNS->edge[eNPlusEdge2].flow == 1    /* N(-) */)
                    {
                        /* decrement triple bond on terminal N# */
                        pe = pBNS->edge + pBNS->vert[i].iedge[0];
                    }
                    else
                    {/* 5. N#N(+)-N(+)# */
                        if (pBNS->edge[eNMinusEdge].flow == 0 &&  /* N */
                             pBNS->edge[eNMinusEdge1].flow == 0 && pBNS->edge[eNPlusEdge1].flow == 0 && /* N(+) */
                             pBNS->edge[eNMinusEdge2].flow == 0 && pBNS->edge[eNPlusEdge2].flow == 0    /* N(+) */)
                        {
                            /* decrement triple bond on terminal N# */
                            pe = pBNS->edge + pBNS->vert[i].iedge[0];
                        }
                        else
                        {
                            pe = NULL; /* unknown case */
                        }
                    }
                }
            }
        }

        if (pe)
        {
            SetForbiddenEdgeMask( pBNS, &AllChargeEdges, forbidden_edge_mask );
            RemoveForbiddenEdgeMask( pBNS, &NNNChargeEdges, forbidden_edge_mask );

            v1 = pe->neighbor1;
            v2 = pe->neighbor12 ^ v1;
            pe->flow--;
            pBNS->vert[v1].st_edge.flow--;
            pBNS->vert[v2].st_edge.flow--;
            pBNS->tot_st_flow -= 2;

            pe->forbidden |= forbidden_edge_mask;

            ret = RunBnsTestOnce( pBNS, pBD, pVA, &vPathStart, &vPathEnd, &nPathLen,
                                  &nDeltaH, &nDeltaCharge, &nNumVisitedAtoms );

            if (ret == 1 && ( (vPathEnd == v1 && vPathStart == v2) ||
                (vPathEnd == v2 && vPathStart == v1) ) /*&& nDeltaCharge <= 2*/) /* djb-rwth: addressing LLVM warnings */
            {
                ret = RunBnsRestoreOnce( pBNS, pBD, pVA, pTCGroups );
                ( *pnNumRunBNS )++;
                *pnTotalDelta += ret;
                num_success++;
                /* fix charges on N(-)=N(+)=N- */
                RemoveFromEdgeListByValue( &NNNChargeEdges, eNMinusEdge );
                RemoveFromEdgeListByValue( &NNNChargeEdges, eNMinusEdge1 );
                RemoveFromEdgeListByValue( &NNNChargeEdges, eNPlusEdge1 );
                RemoveFromEdgeListByValue( &NNNChargeEdges, eNMinusEdge2 );
                RemoveFromEdgeListByValue( &NNNChargeEdges, eNPlusEdge2 );
            }
            else
            {
                pe->flow++;
                pBNS->vert[v1].st_edge.flow++;
                pBNS->vert[v2].st_edge.flow++;
                pBNS->tot_st_flow += 2;
                num_failed++;
            }
            pe->forbidden &= inv_forbidden_edge_mask;
            RemoveForbiddenEdgeMask( pBNS, &AllChargeEdges, forbidden_edge_mask );
        }
    }

    /* 3rd attempt */

    /*
    AllChargeEdges.num_edges = 0;
    AllNNNTermAtoms.num_edges = 0;
    NNNChargeEdges.num_edges = 0;
    */
    for (i = 0; i < num_at && 0 <= ret; i++)
    {

        eNMinusEdge = pVA[i].nCMinusGroupEdge - 1;
        /*eNPlusEdge = pVA[i].nCPlusGroupEdge - 1;*/

        if (0 <= eNMinusEdge &&
             at2[i].valence == 1 &&
             at2[i].num_H == 0 &&
             at2[i].radical == 0 &&
             pVA[i].cNumValenceElectrons == 5 &&  /* terminal N# */

             at2[j = at2[i].neighbor[0]].valence == 2 &&
             at2[j].num_H == 0 &&
             at2[j].radical == 0 &&
             pVA[j].cNumValenceElectrons == 5 &&
             ( eNMinusEdge1 = pVA[j].nCMinusGroupEdge - 1 ) >= 0 &&
             ( eNPlusEdge1 = pVA[j].nCPlusGroupEdge - 1 ) >= 0 &&
             !pBNS->edge[eNMinusEdge1].forbidden &&
             !pBNS->edge[eNPlusEdge1].forbidden &&

             at2[k = at2[j].neighbor[at2[j].neighbor[0] == i]].valence == 2 &&
             at2[k].num_H == 0 &&
             at2[k].radical == 0 &&
             pVA[k].cNumValenceElectrons == 5 &&
             ( eNMinusEdge2 = pVA[k].nCMinusGroupEdge - 1 ) >= 0 &&
             ( eNPlusEdge2 = pVA[k].nCPlusGroupEdge - 1 ) >= 0 &&
             !pBNS->edge[eNMinusEdge2].forbidden &&
             !pBNS->edge[eNPlusEdge2].forbidden &&

             pVA[i].cnListIndex > 0 &&
             cnList[pVA[i].cnListIndex - 1].bits == cn_bits_MN)
        {
            /* found N#N(+)-N~ or N(-)=N-N= where the last N (at2[k]) may be charged */
            NNNChargeEdges.num_edges = 0;

            eNFlowerEdge1 = GetChargeFlowerUpperEdge( pBNS, pVA, eNPlusEdge1 );
            eNFlowerEdge2 = GetChargeFlowerUpperEdge( pBNS, pVA, eNPlusEdge2 );

            /* 1. N(-)=N(+)=N- */
            if (pBNS->edge[eNMinusEdge].flow == 1 &&  /* N(-) */
                 pBNS->edge[eNMinusEdge1].flow == 0 && pBNS->edge[eNPlusEdge1].flow == 0 && /* N(+) */
                 pBNS->edge[eNMinusEdge2].flow == 0 && pBNS->edge[eNPlusEdge2].flow == 1    /* N */)
            {
                /* fix charges on N(-)=N(+)=N- */
                if ((ret = AddToEdgeList( &CarbonChargeEdges, eNMinusEdge, INC_EDGE_LIST ))) /* djb-rwth: addressing LLVM warning */
                {
                    goto exit_function;
                }
                if ((ret = AddToEdgeList( &CarbonChargeEdges, eNPlusEdge1, INC_EDGE_LIST ))) /* djb-rwth: addressing LLVM warning */
                {
                    goto exit_function;
                }
                if ((ret = AddToEdgeList( &CarbonChargeEdges, eNMinusEdge1, INC_EDGE_LIST ))) /* djb-rwth: addressing LLVM warning */
                {
                    goto exit_function;
                }
                if ((ret = AddToEdgeList( &CarbonChargeEdges, eNPlusEdge2, INC_EDGE_LIST ))) /* djb-rwth: addressing LLVM warning */
                {
                    goto exit_function;
                }
                if ((ret = AddToEdgeList( &CarbonChargeEdges, eNMinusEdge2, INC_EDGE_LIST ))) /* djb-rwth: addressing LLVM warning */
                {
                    goto exit_function;
                }
                continue; /* already good */
            }
            /* 2. N#N(+)-N= */
            if (pBNS->edge[eNMinusEdge].flow == 0 && /* N */
                 pBNS->edge[eNMinusEdge1].flow == 0 && pBNS->edge[eNPlusEdge1].flow == 0 && /* N(+) */
                 pBNS->edge[eNMinusEdge2].flow == 0 && pBNS->edge[eNPlusEdge2].flow == 1    /* N */)
            {
                /* unfix (-) edge on terminal N# */
                if ((ret = AddToEdgeList( &NNNChargeEdges, eNPlusEdge1, INC_EDGE_LIST ))) /* djb-rwth: addressing LLVM warning */
                {
                    goto exit_function;
                }
                if ((ret = AddToEdgeList( &NNNChargeEdges, eNMinusEdge1, INC_EDGE_LIST ))) /* djb-rwth: addressing LLVM warning */
                {
                    goto exit_function;
                }
                if ((ret = AddToEdgeList( &NNNChargeEdges, eNPlusEdge2, INC_EDGE_LIST ))) /* djb-rwth: addressing LLVM warning */
                {
                    goto exit_function;
                }
                if ((ret = AddToEdgeList( &NNNChargeEdges, eNMinusEdge2, INC_EDGE_LIST ))) /* djb-rwth: addressing LLVM warning */
                {
                    goto exit_function;
                }
                pe = pBNS->edge + pBNS->vert[i].iedge[0];
                /* djb-rwth: removing redundant code */
                nDeltaChargeMax = ( num_failed && !num_success && pStruct->nNumRemovedProtonsMobHInChI > 0 ) ? 2 : 0;
            }
            else
            {
                /* 3. N(-)=N-N= */
                if (pBNS->edge[eNMinusEdge].flow == 1 && /* N(-) */
                     pBNS->edge[eNMinusEdge1].flow == 0 && pBNS->edge[eNPlusEdge1].flow == 1 && /* N */
                     pBNS->edge[eNMinusEdge2].flow == 0 && pBNS->edge[eNPlusEdge2].flow == 1    /* N */)
                {
                    /* unfix (+) edge on middle N */
                    if ((ret = AddToEdgeList( &NNNChargeEdges, eNMinusEdge, INC_EDGE_LIST ))) /* djb-rwth: addressing LLVM warning */
                    {
                        goto exit_function;
                    }
                    if ((ret = AddToEdgeList( &NNNChargeEdges, eNMinusEdge1, INC_EDGE_LIST ))) /* djb-rwth: addressing LLVM warning */
                    {
                        goto exit_function;
                    }
                    if ((ret = AddToEdgeList( &NNNChargeEdges, eNPlusEdge2, INC_EDGE_LIST ))) /* djb-rwth: addressing LLVM warning */
                    {
                        goto exit_function;
                    }
                    if ((ret = AddToEdgeList( &NNNChargeEdges, eNMinusEdge2, INC_EDGE_LIST ))) /* djb-rwth: addressing LLVM warning */
                    {
                        goto exit_function;
                    }
                    if (NO_VERTEX != eNFlowerEdge1 &&
                        ( ret = AddToEdgeList( &NNNChargeEdges, eNFlowerEdge1, INC_EDGE_LIST ) ))
                    {
                        goto exit_function;
                    }
                    /* decrement flow on (+) charge edge of the middle =N- */
                    pe = pBNS->edge + eNPlusEdge1;
                    nDeltaChargeMax = 2;
                }
                else
                {
                    /* 4. N#N(+)-N(-)- */
                    if (pBNS->edge[eNMinusEdge].flow == 0 &&  /* N */
                         pBNS->edge[eNMinusEdge1].flow == 0 && pBNS->edge[eNPlusEdge1].flow == 0 && /* N(+) */
                         pBNS->edge[eNMinusEdge2].flow == 1 && pBNS->edge[eNPlusEdge2].flow == 1    /* N(-) */)
                    {
                        /* unfix (-) edge on the 1st and 3rd N */
                        if ((ret = AddToEdgeList( &NNNChargeEdges, eNPlusEdge1, INC_EDGE_LIST ))) /* djb-rwth: addressing LLVM warning */
                        {
                            goto exit_function;
                        }
                        if ((ret = AddToEdgeList( &NNNChargeEdges, eNMinusEdge1, INC_EDGE_LIST ))) /* djb-rwth: addressing LLVM warning */
                        {
                            goto exit_function;
                        }
                        if ((ret = AddToEdgeList( &NNNChargeEdges, eNPlusEdge2, INC_EDGE_LIST ))) /* djb-rwth: addressing LLVM warning */
                        {
                            goto exit_function;
                        }
                        /* decrement triple bond on terminal N# */
                        pe = pBNS->edge + pBNS->vert[i].iedge[0];
                        nDeltaChargeMax = 0;
                    }
                    else
                    {
                        /* 5. N#N(+)-N(+)# */
                        if (pBNS->edge[eNMinusEdge].flow == 0 &&  /* N */
                             pBNS->edge[eNMinusEdge1].flow == 0 && pBNS->edge[eNPlusEdge1].flow == 0 && /* N(+) */
                             pBNS->edge[eNMinusEdge2].flow == 0 && pBNS->edge[eNPlusEdge2].flow == 0    /* N(+) */)
                        {
                            /* unfix (-) edge on the 1st and (+) edge on the 3rd N */
                            if ((ret = AddToEdgeList( &NNNChargeEdges, eNPlusEdge1, INC_EDGE_LIST ))) /* djb-rwth: addressing LLVM warning */
                            {
                                goto exit_function;
                            }
                            if ((ret = AddToEdgeList( &NNNChargeEdges, eNMinusEdge1, INC_EDGE_LIST ))) /* djb-rwth: addressing LLVM warning */
                            {
                                goto exit_function;
                            }
                            if ((ret = AddToEdgeList( &NNNChargeEdges, eNMinusEdge2, INC_EDGE_LIST ))) /* djb-rwth: addressing LLVM warning */
                            {
                                goto exit_function;
                            }
                            /* decrement triple bond on terminal N# */
                            pe = pBNS->edge + pBNS->vert[i].iedge[0];
                            nDeltaChargeMax = 0;
                        }
                        else
                        {
                            continue;
                        }
                    }
                }
            }

            if (NO_VERTEX != eNFlowerEdge1 && !pBNS->edge[eNFlowerEdge1].flow)
            {
                if ((ret = AddToEdgeList( &NNNChargeEdges, eNFlowerEdge1, INC_EDGE_LIST ))) /* djb-rwth: addressing LLVM warning */
                {
                    goto exit_function;
                }
            }
            if (NO_VERTEX != eNFlowerEdge2 && !pBNS->edge[eNFlowerEdge2].flow)
            {
                if ((ret = AddToEdgeList( &NNNChargeEdges, eNFlowerEdge2, INC_EDGE_LIST ))) /* djb-rwth: addressing LLVM warning */
                {
                    goto exit_function;
                }
            }

            v1 = pe->neighbor1;
            v2 = pe->neighbor12 ^ v1;
            pe->flow--;
            pBNS->vert[v1].st_edge.flow--;
            pBNS->vert[v2].st_edge.flow--;
            pBNS->tot_st_flow -= 2;

            pe->forbidden |= forbidden_edge_mask;

            if (!CarbonChargeEdges.num_edges)
            {
                /* do not let carbon atoms get charged */
                AllocEdgeList( &CarbonChargeEdges, INC_EDGE_LIST );
                if (0 > ( ret = ForbidCarbonChargeEdges( pBNS, pTCGroups, &CarbonChargeEdges, forbidden_edge_mask ) ))
                {
                    goto exit_function;
                }
            }
            else
            {
                SetForbiddenEdgeMask( pBNS, &CarbonChargeEdges, forbidden_edge_mask );
            }
            SetForbiddenEdgeMask( pBNS, &NNNChargeEdges, forbidden_edge_mask );

            ret = RunBnsTestOnce( pBNS, pBD, pVA, &vPathStart, &vPathEnd, &nPathLen,
                                  &nDeltaH, &nDeltaCharge, &nNumVisitedAtoms );

            if (ret == 1 && ( (vPathEnd == v1 && vPathStart == v2) ||
                (vPathEnd == v2 && vPathStart == v1) ) && nDeltaCharge <= nDeltaChargeMax) /* djb-rwth: addressing LLVM warnings */
            {
                ret = RunBnsRestoreOnce( pBNS, pBD, pVA, pTCGroups );
                ( *pnNumRunBNS )++;
                *pnTotalDelta += ret;
                num_success++;
                /* fix charges on N(-)=N(+)=N- */
                if ((ret = AddToEdgeList( &CarbonChargeEdges, eNMinusEdge, INC_EDGE_LIST ))) /* djb-rwth: addressing LLVM warning */
                {
                    goto exit_function;
                }
                if ((ret = AddToEdgeList( &CarbonChargeEdges, eNPlusEdge1, INC_EDGE_LIST ))) /* djb-rwth: addressing LLVM warning */
                {
                    goto exit_function;
                }
                if ((ret = AddToEdgeList( &CarbonChargeEdges, eNMinusEdge1, INC_EDGE_LIST ))) /* djb-rwth: addressing LLVM warning */
                {
                    goto exit_function;
                }
                if ((ret = AddToEdgeList( &CarbonChargeEdges, eNPlusEdge2, INC_EDGE_LIST ))) /* djb-rwth: addressing LLVM warning */
                {
                    goto exit_function;
                }
                if ((ret = AddToEdgeList( &CarbonChargeEdges, eNMinusEdge2, INC_EDGE_LIST ))) /* djb-rwth: addressing LLVM warning */
                {
                    goto exit_function;
                }
            }
            else
            {
                pe->flow++;
                pBNS->vert[v1].st_edge.flow++;
                pBNS->vert[v2].st_edge.flow++;
                pBNS->tot_st_flow += 2;
                num_failed++;
            }
            RemoveForbiddenEdgeMask( pBNS, &CarbonChargeEdges, forbidden_edge_mask );
            RemoveForbiddenEdgeMask( pBNS, &NNNChargeEdges, forbidden_edge_mask );
            pe->forbidden &= inv_forbidden_edge_mask;
            /*pBNS->edge[eNPlusEdge].forbidden &= inv_forbidden_edge_mask;*/ /* BC: array index out of range */
        }
    }
    RemoveForbiddenEdgeMask( pBNS, &CarbonChargeEdges, forbidden_edge_mask );


exit_function:

    AllocEdgeList( &CarbonChargeEdges, EDGE_LIST_FREE );
    AllocEdgeList( &AllChargeEdges, EDGE_LIST_FREE );
    AllocEdgeList( &NNNChargeEdges, EDGE_LIST_FREE );
    AllocEdgeList( &CurNNNChargeEdges, EDGE_LIST_FREE );
    AllocEdgeList( &AllNNNTermAtoms, EDGE_LIST_FREE );
    AllocEdgeList( &AllNIIIChargeEdges, EDGE_LIST_FREE );

    return ret;
#undef INC_EDGE_LIST
}


/****************************************************************************/
int EliminateNitrogen5Val3Bonds( BN_STRUCT *pBNS,
                                 BN_DATA *pBD,
                                 StrFromINChI *pStruct,
                                 inp_ATOM *at,
                                 inp_ATOM *at2,
                                 VAL_AT *pVA,
                                 ALL_TC_GROUPS *pTCGroups,
                                 int *pnNumRunBNS,
                                 int *pnTotalDelta,
                                 int forbidden_edge_mask )
{
    int i, j, k, bForbiddenCarbonCharges, ret2, ret;
    int num_at = pStruct->num_atoms;
    int num_deleted_H = pStruct->num_deleted_H;
    int len_at = num_at + num_deleted_H;
    int inv_forbidden_edge_mask = ~forbidden_edge_mask;
    EDGE_LIST CarbonChargeEdges;

    ret = 0;
    bForbiddenCarbonCharges = 0;
    AllocEdgeList( &CarbonChargeEdges, EDGE_LIST_CLEAR );

    memcpy(at2, at, len_at * sizeof(at2[0]));
    pStruct->at = at2;
    ret2 = CopyBnsToAtom( pStruct, pBNS, pVA, pTCGroups, 1 );
    if (ret2 < 0)
    {
        ret = ret2;
        goto exit_function;
    }

    /* forbid creation of other N(V) atoms */
    /* fix single bonds to metals */
    for (i = 0; i < num_at; i++)
    {
        if (pVA[i].cNumValenceElectrons == 5 &&
             0 <= ( k = GetChargeFlowerUpperEdge( pBNS, pVA, pVA[i].nCPlusGroupEdge - 1 ) ) &&
             1 == pBNS->edge[k].flow)
        {
            pBNS->edge[k].forbidden |= forbidden_edge_mask;
        }
        else
            if (pVA[i].cMetal)
            {
                for (j = 0; j < at2[i].valence; j++)
                {
                    if (BOND_TYPE_SINGLE == ( at2[i].bond_type[j] & BOND_TYPE_MASK ))
                    {
                        pBNS->edge[pBNS->vert[i].iedge[j]].forbidden |= forbidden_edge_mask;
                    }
                }
            }
    }

    /*------------------------------------------------------------------------------
                 (+)  single line => flow = 0                            (+)-(Y)=(+)super
            01  //    double line => flow = 1                fix-> 01   // <-- fix
         1 --- 0                                                 1 === 0
          \\ //         edge eij connects vertices i < j:         \   /  02
        12  2   02 <--- edge number: e02 connects vertices v0   12  2(..) <- double 'radical'
            |                        v0 and v2                      |
           =N=      vertex N has number i                          =N=
            |                                                       |
    --------------------------------------------------------------------------------*/
    for (i = 0; i < num_at; i++)
    {
        if (pVA[i].cNumValenceElectrons == 5 && at2[i].valence == 3 &&
             at2[i].chem_bonds_valence == 5 && !at2[i].charge && !at2[i].radical &&
             !( at2[i].endpoint || (pStruct->endpoint && pStruct->endpoint[i]) ) && pVA[i].cnListIndex > 0 &&
             cnList[pVA[i].cnListIndex - 1].bits == cn_bits_NPN &&
             pVA[i].nCPlusGroupEdge > 0) /* djb-rwth: addressing LLVM warning */
        {

            Vertex v, v0 = NO_VERTEX, v1 = NO_VERTEX, v2 = NO_VERTEX;
            EdgeIndex iePlus, ie, ie12 = NO_VERTEX; /* djb-rwth: removing redundant variables */
            BNS_VERTEX *pv0, *pv2 = NULL; /* djb-rwth: removing redundant variables */
            BNS_EDGE   *pePlus, *pe, *pe12 = NULL, *pe02 = NULL, *pe01 = NULL;
            Vertex     vPathStart, vPathEnd;
            int        nPathLen;
            int        nDeltaH, nDeltaCharge, nNumVisitedAtoms;

            iePlus = pVA[i].nCPlusGroupEdge - 1;
            pePlus = pBNS->edge + iePlus;

            v0 = IS_BNS_VT_C_GR( pBNS->vert[pePlus->neighbor1].type ) ?
                ( pePlus->neighbor1 ^ pePlus->neighbor12 ) : pePlus->neighbor1;
            pv0 = pBNS->vert + v0;
            for (j = 0; j < pv0->num_adj_edges; j++)
            {
                ie = pv0->iedge[j];
                if (ie == iePlus)
                {
                    continue;
                }
                pe = pBNS->edge + ie;
                if (pe->flow == 1 && v2 == NO_VERTEX)
                {
                    /* 0 - 2, edge 02 */
                    v2 = pe->neighbor12 ^ v0;
                    pv2 = pBNS->vert + v2;
                    /* djb-rwth: removing redundant code */
                    pe02 = pe;
                }
                else
                {
                    if (pe->flow == 0 && v1 == NO_VERTEX)
                    {
                        /* 0 - 1, edge 01 */
                        v1 = pe->neighbor12 ^ v0;
                        /* djb-rwth: removing redundant code */
                        /* djb-rwth: removing redundant code */
                        pe01 = pe;
                    }
                    else
                    {
                        ret = RI_ERR_PROGR;
                        goto exit_function;
                    }
                }
            }
            if (v1 == NO_VERTEX || v2 == NO_VERTEX)
            {
                ret = RI_ERR_PROGR;
                goto exit_function;
            }
            for (j = 0; j < pv2->num_adj_edges; j++)
            {
                ie = pv2->iedge[j];
                pe = pBNS->edge + ie;
                v = pe->neighbor12 ^ v2;
                if (v == v0 || v == i)
                {
                    continue;
                }
                else
                {
                    if (v == v1 && pe->flow == 1)
                    {
                        /* 1 - 2, edge 12 */
                        ie12 = ie;
                        pe12 = pe;
                    }
                    else
                    {
                        ret = RI_ERR_PROGR;
                        goto exit_function;
                    }
                }
            }
            if (ie12 == NO_VERTEX)
            {
                ret = RI_ERR_PROGR;
                goto exit_function;
            }
            /* rearrange cap and flow, forbid 2 edges */
            pe01->flow = 1;
            pe12->flow = 0;
            pe02->flow = 0;
            pv2->st_edge.flow -= 2;
            pBNS->tot_st_flow -= 2;
            pePlus->forbidden |= forbidden_edge_mask;
            pe01->forbidden |= forbidden_edge_mask;

            if (!bForbiddenCarbonCharges)
            {
                if (0 > ( ret = ForbidCarbonChargeEdges( pBNS, pTCGroups, &CarbonChargeEdges, forbidden_edge_mask ) ))
                {
                    goto exit_function;
                }
                bForbiddenCarbonCharges = 1;
            }


            ret = RunBnsTestOnce( pBNS, pBD, pVA, &vPathStart, &vPathEnd, &nPathLen,
                                  &nDeltaH, &nDeltaCharge, &nNumVisitedAtoms );
            if (ret == 1 && vPathEnd == v2 && vPathStart == v2 && nDeltaCharge <= ( pVA[i].cNumBondsToMetal ? 2 : 0 ))
            {
                ret = RunBnsRestoreOnce( pBNS, pBD, pVA, pTCGroups );
            }
            else
            {
                pe01->flow = 0;
                pe12->flow = 1;
                pe02->flow = 1;
                pv2->st_edge.flow += 2;
                pBNS->tot_st_flow += 2;
            }
            pePlus->forbidden &= inv_forbidden_edge_mask;
            pe01->forbidden &= inv_forbidden_edge_mask;

            if (ret < 0)
            {
                goto exit_function;
            }
            else
            {
                if (ret)
                {
                    memcpy(at2, at, len_at * sizeof(at2[0]));
                    pStruct->at = at2;
                    ret2 = CopyBnsToAtom( pStruct, pBNS, pVA, pTCGroups, 1 );
                    if (ret2 < 0)
                    {
                        ret = ret2;
                        goto exit_function;
                    }
                }
            }
        }
    }

exit_function:

    /* allow creation of other N(V) atoms */
    for (i = 0; i < num_at; i++)
    {
        if (pVA[i].cNumValenceElectrons == 5 &&
             0 <= ( k = GetChargeFlowerUpperEdge( pBNS, pVA, pVA[i].nCPlusGroupEdge - 1 ) ) &&
             1 == pBNS->edge[k].flow && ( pBNS->edge[k].forbidden & forbidden_edge_mask ))
        {
            pBNS->edge[k].forbidden &= inv_forbidden_edge_mask;
        }
        else
        {
            if (pVA[i].cMetal)
            {
                for (j = 0; j < at2[i].valence; j++)
                {
                    if (BOND_TYPE_SINGLE == ( at2[i].bond_type[j] & BOND_TYPE_MASK ))
                    {
                        pBNS->edge[pBNS->vert[i].iedge[j]].forbidden &= inv_forbidden_edge_mask;
                    }
                }
            }
        }
    }
    RemoveForbiddenEdgeMask( pBNS, &CarbonChargeEdges, forbidden_edge_mask );
    AllocEdgeList( &CarbonChargeEdges, EDGE_LIST_FREE );

    return ret;
}


/****************************************************************************/
int Convert_SIV_to_SVI( BN_STRUCT *pBNS,
                        BN_DATA *pBD,
                        StrFromINChI *pStruct,
                        inp_ATOM *at,
                        inp_ATOM *at2,
                        VAL_AT *pVA,
                        ALL_TC_GROUPS *pTCGroups,
                        int *pnNumRunBNS,
                        int *pnTotalDelta,
                        int forbidden_edge_mask )
{
    int i, j, k, neigh, bForbiddenCarbonCharges, nFlowerEdge, delta, ret2, ret;
    int num_at = pStruct->num_atoms;
    int num_deleted_H = pStruct->num_deleted_H;
    int len_at = num_at + num_deleted_H;
    int inv_forbidden_edge_mask = ~forbidden_edge_mask;
    EDGE_LIST CarbonChargeEdges, FlowerEdgesList;

    ret = 0;
    bForbiddenCarbonCharges = 0;
    AllocEdgeList( &CarbonChargeEdges, EDGE_LIST_CLEAR );
    AllocEdgeList( &FlowerEdgesList, EDGE_LIST_CLEAR );

    memcpy(at2, at, len_at * sizeof(at2[0]));
    pStruct->at = at2;
    ret2 = CopyBnsToAtom( pStruct, pBNS, pVA, pTCGroups, 1 );
    if (ret2 < 0)
    {
        ret = ret2;
        goto exit_function;
    }

    /* forbid creation of other S(IV) atoms */
    /* fix single bonds to metals and (N(IV), flow=1), (S(IV), flow=0) */
    for (i = 0; i < num_at; i++)
    {
        if (( pVA[i].cNumValenceElectrons == 5 /* N(IV)*/ || pVA[i].cNumValenceElectrons == 6 /* S(VI)*/ ) &&
             0 <= ( k = GetChargeFlowerUpperEdge( pBNS, pVA, pVA[i].nCPlusGroupEdge - 1 ) ) &&
             !pBNS->edge[k].forbidden &&
             6 == pVA[i].cNumValenceElectrons + pBNS->edge[k].flow)
        {

            pBNS->edge[k].forbidden |= forbidden_edge_mask;
            if ((ret = AddToEdgeList( &FlowerEdgesList, k, 64 ))) /* djb-rwth: addressing LLVM warning */
            {
                goto exit_function;
            }
        }
        else
        {
            if (pVA[i].cMetal)
            {
                for (j = 0; j < at2[i].valence; j++)
                {
                    if (BOND_TYPE_SINGLE == ( at2[i].bond_type[j] & BOND_TYPE_MASK ))
                    {

                        pBNS->edge[k = pBNS->vert[i].iedge[j]].forbidden |= forbidden_edge_mask;
                        if ((ret = AddToEdgeList( &FlowerEdgesList, k, 64 ))) /* djb-rwth: addressing LLVM warning */
                        {
                            goto exit_function;
                        }
                    }
                }
            }
            else
            {
                /* fix bonds to neighbors of S(IV) if they are not O,S,Se,Te with 2 or more bonds */
                 /* exactly same if(..) as below */
                if (pVA[i].cNumValenceElectrons == 6 && at2[i].valence == 4 &&
                     at2[i].chem_bonds_valence == 4 && !at2[i].charge && !at2[i].radical &&
                     !at2[i].endpoint && pVA[i].cnListIndex > 0 &&
                     cnList[pVA[i].cnListIndex - 1].bits == cn_bits_NPN &&
                     0 <= ( nFlowerEdge = GetChargeFlowerUpperEdge( pBNS, pVA, pVA[i].nCPlusGroupEdge - 1 ) ) &&
                     pBNS->edge[nFlowerEdge].flow > 0)
                {

                    for (j = 0; j < at2[i].valence; j++)
                    {
                        neigh = at2[i].neighbor[j];
                        if (pVA[neigh].cNumValenceElectrons != 6 && at2[neigh].valence > 1)
                        {
                            k = pBNS->vert[i].iedge[j];
                            if (!pBNS->edge[k].forbidden)
                            {
                                if ((ret = AddToEdgeList( &FlowerEdgesList, k, 64 ))) /* djb-rwth: addressing LLVM warning */
                                {
                                    goto exit_function;
                                }
                                pBNS->edge[k].forbidden |= forbidden_edge_mask;
                            }
                        }
                    }
                }
            }
        }
    }

    /*------------------------------------------------------------------------------
                        example: struct #301,
      |          |               disconnected porphyrin with four -SO3(-)
     -S-   =>   =S=
      |          |

    -------------------------------------------------------------------------------*/

    /*-------------------------------------------------------------------------------
     found:                                       super(+)=(Y)        super(+)=(Y)
                                                              \                   \
             (+)  single line => flow = 0                     (+)                 (+)
        01  //    double line => flow = 1         fix-> 01   //             01   //
     1 === 0      triple line => flow = 2          (.)1 --- 0(.)  --->    1 --- 0
      \   /       edge eij connects vertices i<j:      \   /  02  run      \\ //  02
    12  2   02 <--- edge number: e02 connects        12  2        BFS    12  2
       |||              vertices v0 and v2              |||                  |
       -S-      vertex S has number i                   -S-                 =S=
       / \                                              / \                 / \
    --------------------------------------------------------------------------------*/
    for (i = 0; i < num_at; i++)
    {
        if (pVA[i].cNumValenceElectrons == 6 && at2[i].valence == 4 &&
             at2[i].chem_bonds_valence == 4 && !at2[i].charge && !at2[i].radical &&
             !at2[i].endpoint && pVA[i].cnListIndex > 0 &&
             cnList[pVA[i].cnListIndex - 1].bits == cn_bits_NPN &&
             /* 01 is nFlowerEdge */
             0 <= ( nFlowerEdge = GetChargeFlowerUpperEdge( pBNS, pVA, pVA[i].nCPlusGroupEdge - 1 ) ) &&
             pBNS->edge[nFlowerEdge].flow > 0)
        {

            Vertex     v1 = NO_VERTEX, v2 = NO_VERTEX;
            BNS_VERTEX *pv1, *pv2;
            BNS_EDGE   *pe;
            Vertex     vPathStart, vPathEnd;
            int        nPathLen;
            int        nDeltaH, nDeltaCharge, nNumVisitedAtoms;

            if (!bForbiddenCarbonCharges)
            {
                if (0 > ( ret = ForbidCarbonChargeEdges( pBNS, pTCGroups, &CarbonChargeEdges, forbidden_edge_mask ) ))
                {
                    goto exit_function;
                }
                bForbiddenCarbonCharges = 1;
            }

            delta = 1;
            pe = pBNS->edge + nFlowerEdge;                 /* edge  01 */
            pv1 = pBNS->vert + ( v1 = pe->neighbor1 );       /* vertex 0 */
            pv2 = pBNS->vert + ( v2 = pe->neighbor12 ^ v1 ); /* vertex 1 */

            pe->forbidden |= forbidden_edge_mask;
            pe->flow -= delta;
            pv1->st_edge.flow -= delta;
            pv2->st_edge.flow -= delta;
            pBNS->tot_st_flow -= 2 * delta;

            ret = RunBnsTestOnce( pBNS, pBD, pVA, &vPathStart, &vPathEnd, &nPathLen,
                                  &nDeltaH, &nDeltaCharge, &nNumVisitedAtoms );
            if (ret == 1 &&
                ( (vPathEnd == v1 && vPathStart == v2) || (vPathEnd == v2 && vPathStart == v1) ) &&
                 nDeltaCharge <= ( pVA[i].cNumBondsToMetal ? 2 : 0 )) /* djb-rwth: addressing LLVM warnings */
            {
                ret = RunBnsRestoreOnce( pBNS, pBD, pVA, pTCGroups );
            }
            else
            {
                pe->forbidden &= inv_forbidden_edge_mask;
                pe->flow += delta;
                pv1->st_edge.flow += delta;
                pv2->st_edge.flow += delta;
                pBNS->tot_st_flow += 2 * delta;
            }
            if (ret < 0)
            {
                goto exit_function;
            }
            else
            {
                if (ret)
                {
                    memcpy(at2, at, len_at * sizeof(at2[0]));
                    pStruct->at = at2;
                    ret2 = CopyBnsToAtom( pStruct, pBNS, pVA, pTCGroups, 1 );
                    if (ret2 < 0)
                    {
                        ret = ret2;
                        goto exit_function;
                    }
                    /* store the fixed edge to unfix it upon exit */
                    if ((ret = AddToEdgeList( &FlowerEdgesList, nFlowerEdge, 64 ))) /* djb-rwth: addressing LLVM warning */
                    {
                        goto exit_function;
                    }
                }
            }
        }
    }

exit_function:

    RemoveForbiddenEdgeMask( pBNS, &CarbonChargeEdges, forbidden_edge_mask );
    AllocEdgeList( &CarbonChargeEdges, EDGE_LIST_FREE );
    RemoveForbiddenEdgeMask( pBNS, &FlowerEdgesList, forbidden_edge_mask );
    AllocEdgeList( &FlowerEdgesList, EDGE_LIST_FREE );

    return ret;
}


/****************************************************************************

  =N(+)=O       =N-O(-)
            =>
   M(q)         M(q+2)

****************************************************************************/
int PlusFromDB_N_DB_O_to_Metal( BN_STRUCT *pBNS,
                                BN_DATA *pBD,
                                StrFromINChI *pStruct,
                                inp_ATOM *at,
                                inp_ATOM *at2,
                                VAL_AT *pVA,
                                ALL_TC_GROUPS *pTCGroups,
                                int *pnNumRunBNS,
                                int *pnTotalDelta,
                                int forbidden_edge_mask )
{
    int i, j, k, n, delta, ret2, ret, num_NO, num_M; /* djb-rwth: removing redundant variables */
    int num_at = pStruct->num_atoms;
    int num_deleted_H = pStruct->num_deleted_H;
    int len_at = num_at + num_deleted_H;
    int inv_forbidden_edge_mask = ~forbidden_edge_mask;
    EDGE_LIST CarbonChargeEdges, NO_ChargeEdgeList, NO_EdgeList;

    Vertex     v1, v2;
    BNS_VERTEX *pv1, *pv2;
    BNS_EDGE   *pe;
    Vertex     vPathStart, vPathEnd;
    int        nPathLen;
    int        nDeltaH, nDeltaCharge, nNumVisitedAtoms;


    if (!pTCGroups->num_metal_atoms)
    {
        return 0;
    }

    ret = 0;
    /* djb-rwth: removing redundant code */
    AllocEdgeList( &CarbonChargeEdges, EDGE_LIST_CLEAR ); /* all charges */
    AllocEdgeList( &NO_ChargeEdgeList, EDGE_LIST_CLEAR ); /* charges to be changed */
    AllocEdgeList( &NO_EdgeList, EDGE_LIST_CLEAR );       /* N(+)=O edges */

    memcpy(at2, at, len_at * sizeof(at2[0]));
    pStruct->at = at2;
    ret2 = CopyBnsToAtom( pStruct, pBNS, pVA, pTCGroups, 1 );
    if (ret2 < 0)
    {
        ret = ret2;
        goto exit_function;
    }

    num_NO = num_M = 0;

    /* forbid creation of other S(IV) atoms */
    /* fix single bonds to metals and (N(IV), flow=1), (S(IV), flow=0) */
    for (i = 0; i < num_at; i++)
    {
        if (!pVA[i].cMetal)
        {
            if (( k = pVA[i].nCPlusGroupEdge - 1 ) >= 0 && !pBNS->edge[k].forbidden)
            {
                if ((ret = AddToEdgeList( &CarbonChargeEdges, k, 64 ))) /* djb-rwth: addressing LLVM warning */
                {
                    goto exit_function;
                }
            }
            if (( k = pVA[i].nCMinusGroupEdge - 1 ) >= 0 && !pBNS->edge[k].forbidden)
            {
                if ((ret = AddToEdgeList( &CarbonChargeEdges, k, 64 ))) /* djb-rwth: addressing LLVM warning */
                {
                    goto exit_function;
                }
            }
        }
        else
        {
            num_M++;
        }
        /*
        if ( pVA[i].cMetal )
        {
            if ( (k = pVA[i].nCPlusGroupEdge-1) >= 0 && !pBNS->edge[k].forbidden )
            {
                if ( ret = AddToEdgeList( &NO_ChargeEdgeList, k, 64 ) )
                {
                    goto exit_function;
                }
            }
            if ( (k = pVA[i].nCMinusGroupEdge-1) >= 0 && !pBNS->edge[k].forbidden )
            {
                if ( ret = AddToEdgeList( &NO_ChargeEdgeList, k, 64 ) )
                {
                    goto exit_function;
                }
            }
        }
        else
        */
        if (!pVA[i].cMetal &&
             pVA[i].cNumValenceElectrons == 6 &&
             at2[i].charge == 0 && !at2[i].num_H &&
             1 == at2[i].valence && 2 == at2[i].chem_bonds_valence &&
             pVA[j = at2[i].neighbor[0]].cNumValenceElectrons == 5 &&
             at2[j].charge == 1 && !at2[j].num_H &&
             2 == at2[j].valence && 4 == at2[j].chem_bonds_valence)
        {
            /* found =N(+)=O */
            if (( k = pVA[i].nCMinusGroupEdge - 1 ) >= 0 && !pBNS->edge[k].forbidden /* O */ &&
                ( n = pVA[j].nCPlusGroupEdge - 1 ) >= 0 && !pBNS->edge[j].forbidden /* N */)
            {
                if (( ret = AddToEdgeList( &NO_ChargeEdgeList, k, 64 ) ) ||
                    ( ret = AddToEdgeList( &NO_ChargeEdgeList, n, 64 ) ))
                {
                    goto exit_function;
                }
                k = pBNS->vert[i].iedge[0];  /* N(+)=O bond */
                if (!pBNS->edge[k].forbidden)
                {
                    if ((ret = AddToEdgeList( &NO_EdgeList, k, 64 ))) /* djb-rwth: addressing LLVM warning */
                    {
                        goto exit_function;
                    }
                    num_NO++;
                }
            }
        }
    }
    if (num_M && num_NO)
    {
        SetForbiddenEdgeMask( pBNS, &CarbonChargeEdges, forbidden_edge_mask );
        SetForbiddenEdgeMask( pBNS, &NO_EdgeList, forbidden_edge_mask );
        RemoveForbiddenEdgeMask( pBNS, &NO_ChargeEdgeList, forbidden_edge_mask );
        /* now only N(+), O(-) and metal charges are allowed to change */
        for (i = 0; i < NO_EdgeList.num_edges; i++)
        {
            k = NO_EdgeList.pnEdges[i];
            delta = 1;
            pe = pBNS->edge + k;                 /* edge  N(+)=O */
            pv1 = pBNS->vert + ( v1 = pe->neighbor1 );       /* vertex 0 */
            pv2 = pBNS->vert + ( v2 = pe->neighbor12 ^ v1 ); /* vertex 1 */

            pe->flow -= delta;
            pv1->st_edge.flow -= delta;
            pv2->st_edge.flow -= delta;
            pBNS->tot_st_flow -= 2 * delta;

            ret = RunBnsTestOnce( pBNS, pBD, pVA, &vPathStart, &vPathEnd, &nPathLen,
                                  &nDeltaH, &nDeltaCharge, &nNumVisitedAtoms );
            if (ret == 1 &&
                ( (vPathEnd == v1 && vPathStart == v2) || (vPathEnd == v2 && vPathStart == v1) ) &&
                 nDeltaCharge == 0) /* djb-rwth: addressing LLVM warnings */
            {
                ret = RunBnsRestoreOnce( pBNS, pBD, pVA, pTCGroups );
            }
            else
            {
                pe->forbidden &= inv_forbidden_edge_mask;
                pe->flow += delta;
                pv1->st_edge.flow += delta;
                pv2->st_edge.flow += delta;
                pBNS->tot_st_flow += 2 * delta;
            }
            if (ret < 0)
            {
                goto exit_function;
            }
        }
    }

exit_function:
    RemoveForbiddenEdgeMask( pBNS, &CarbonChargeEdges, forbidden_edge_mask );
    RemoveForbiddenEdgeMask( pBNS, &NO_EdgeList, forbidden_edge_mask );
    AllocEdgeList( &CarbonChargeEdges, EDGE_LIST_FREE );
    AllocEdgeList( &NO_EdgeList, EDGE_LIST_FREE );
    AllocEdgeList( &NO_ChargeEdgeList, EDGE_LIST_FREE );

    return ret;
}


/****************************************************************************/
int MoveMobileHToAvoidFixedBonds( BN_STRUCT *pBNS,
                                  BN_DATA *pBD,
                                  StrFromINChI *pStruct,
                                  inp_ATOM *at,
                                  inp_ATOM *at2,
                                  VAL_AT *pVA,
                                  ALL_TC_GROUPS *pTCGroups,
                                  int *pnNumRunBNS,
                                  int *pnTotalDelta,
                                  int forbidden_edge_mask )
{
    int ret2, ret;
    int num_at = pStruct->num_atoms;
    int num_deleted_H = pStruct->num_deleted_H;
    int len_at = num_at + num_deleted_H;
    int nNumFixedEdges, nNumAdjEdges;

    ret = 0;

    if (pTCGroups->num_tgroups)
    {
        memcpy(at2, at, len_at * sizeof(at2[0]));
        pStruct->at = at2;
        ret2 = CopyBnsToAtom( pStruct, pBNS, pVA, pTCGroups, 1 );
        pStruct->at = at;
        if (ret2 < 0)
        {
            ret = ret2;
            goto exit_function;
        }
#if ( FIND_RING_SYSTEMS == 1 )
        ret2 = MarkRingSystemsInp( at2, num_at, 0 );
        if (ret2 < 0)
        {
            ret = ret2;
            goto exit_function;
        }
#endif
        /* --- forbidden edges --- */
        ret2 = SetForbiddenEdges( pBNS, at2, num_at, forbidden_edge_mask, 0, NULL );

        if (ret2 < 0)
        {
            ret2 = -( ret + 1 );
        }
        nNumFixedEdges = ret2;
        ret = AdjustTgroupsToForbiddenEdges2( pBNS, at2, pVA, num_at, forbidden_edge_mask );
        nNumAdjEdges = ret;
        if (ret)
        {
            pBNS->edge_forbidden_mask |= forbidden_edge_mask;
            ret = RunBnsRestoreOnce( pBNS, pBD, pVA, pTCGroups );
            ( *pnNumRunBNS )++;
            if (ret < 0)
            {
                goto exit_function;
            }
            else
            {
                *pnTotalDelta += ret;
            }
        }
        if (nNumFixedEdges || nNumAdjEdges)
        {
            /* removes this edge mask from ALL edges */
            RemoveForbiddenBondFlowBits( pBNS, forbidden_edge_mask );
        }
    }

exit_function:

    return ret;
}


/****************************************************************************
 Find and eliminate cases when Mobile H endpoint has radical on it
 (typical for wrong P(VI)(=O)3OH)
****************************************************************************/
int RemoveRadFromMobileHEndpoint( BN_STRUCT *pBNS,
                                  BN_DATA *pBD,
                                  StrFromINChI *pStruct,
                                  inp_ATOM *at,
                                  inp_ATOM *at2,
                                  VAL_AT *pVA,
                                  ALL_TC_GROUPS *pTCGroups,
                                  int *pnNumRunBNS,
                                  int *pnTotalDelta,
                                  int forbidden_edge_mask )
{
    int i, num_fixes, tot_num_fixes = 0;

    int ret2, ret;
    int num_at = pStruct->num_atoms;
    int num_deleted_H = pStruct->num_deleted_H;
    int len_at = num_at + num_deleted_H;

    int         itg, j, k, n, m;
    Vertex      vtg1, endpoint0 = NO_VERTEX, endpoint1, endpoint2, centerpoint;
    Vertex      centerpoint_found = NO_VERTEX;
    BNS_VERTEX *ptg1, *pEndp0 = NULL, *pEndp1, *pEndp2, *pCentp, *pCentp_found, *pEndp2_found = NULL;
    BNS_EDGE   *etg0 = NULL, *etg1, *etg2, *ecp0, *ecp1, *ecp2;
    BNS_EDGE   *etg1_found = NULL, *ecp0_found = NULL, *ecp1_found = NULL, *ecp2_found = NULL;
    int         num_endpoints, max_vertices, nMaxAddAtoms = 2; /* djb-rwth: removing redundant variables; fixing oss-fuzz issue #25732 */

    /* djb-rwth: removing redundant code */
    memcpy(at2, at, len_at * sizeof(at2[0]));
    pStruct->at = at2;
    ret2 = CopyBnsToAtom( pStruct, pBNS, pVA, pTCGroups, 1 );
    if (ret2 < 0)
    {
        ret = ret2;
        goto exit_function;
    }
    while (pBNS->tot_st_cap > pBNS->tot_st_flow && pTCGroups->num_tgroups)
    {
        num_fixes = 0;
        for (itg = 0; itg < pTCGroups->num_tgroups; itg++)
        {
            pCentp_found = NULL;
            /* djb-rwth: removing redundant code */
            vtg1 = pTCGroups->pTCG[itg].nVertexNumber;      /* taut group vertex index */
            ptg1 = pBNS->vert + vtg1;                       /* taut group vertex */
            num_endpoints = pTCGroups->pTCG[itg].num_edges;
            for (i = 0; i < num_endpoints; i++)
            {
                etg0 = pBNS->edge + ptg1->iedge[i];         /* edge from t-group to endpoint */
                endpoint0 = etg0->neighbor12 ^ vtg1;        /* taut endpoint vertex index */
                /* djb-rwth: fixing oss-fuzz issues #68494, #25732 */
                max_vertices = pTCGroups->nVertices + nMaxAddAtoms;
                if (endpoint0 < max_vertices)
                {
                    pEndp0 = pBNS->vert + endpoint0;            /* taut endpoint vertex (possible location of mobile H */
                    if (pEndp0->st_edge.cap > pEndp0->st_edge.flow)
                    {
                        /* radical endpoint1 has been detected */
                        /* find a 1-3 centerpoint that has two or more endpoints */
                        /* connected to the t-group vertex by edges with flow>0 and */
                        /* to the centerpoint by edges with flow = 0 */
                        /* after that: (1) increment etg1 flow to eliminate radical */
                        /* (2) increment flow on one of the two other edges to the t-group */
                        /* (3) increment st_cap on the found centerpoint */
                        /* (4) rerun the BNS and re-create the structure */
                        break;
                    }
                }
            }
            if (i == num_endpoints)
            {
                continue;
            }
            if (i < num_endpoints)
            {
                /* tautomeric endpoint found; traverse its t-group edges */
                for (j = 0; j < num_endpoints; j++)
                {
                    if (i == j)
                    {
                        continue; /* avoid the already found radical endpoint */
                    }
                    etg1 = pBNS->edge + ptg1->iedge[j];  /* another edge from t-group to another endpoinr */
                    endpoint1 = etg1->neighbor12 ^ vtg1; /* another endpoint vertex index */
                    pEndp1 = pBNS->vert + endpoint1;     /* another endpoint vertex */
                    if (pEndp1->st_edge.cap > pEndp1->st_edge.flow)
                    {
                        continue; /* one more radical-endpoint! What is going on here??? */
                    }
                    if (!etg1->flow)
                    {
                        continue; /* avoid enpoints that do not have an attachment */
                    }
                    if (!( pEndp1->type & BNS_VERT_TYPE_ENDPOINT ))
                    {
                        continue; /* should not happen */
                    }
                    /* traverse endpoint1 edges to find a single bond connecting it to the centerpoint */
                    for (k = 0; k < at2[endpoint1].valence; k++)
                    {
                        ecp1 = pBNS->edge + pEndp1->iedge[k];
                        if (ecp1->flow)
                        {
                            continue;
                        }
                        centerpoint = ecp1->neighbor12 ^ endpoint1;
                        pCentp = pBNS->vert + centerpoint;
                        /* traverse centerpoint edges to find a single bond to the 2nd endpoint */
                        for (n = 0; n < at2[centerpoint].valence; n++)
                        {
                            ecp2 = pBNS->edge + pCentp->iedge[n];
                            if (ecp2->flow)
                            {
                                continue;
                            }
                            endpoint2 = ecp2->neighbor12 ^ centerpoint;
                            if (endpoint2 <= endpoint1 || !pVA[endpoint2].nTautGroupEdge)
                            {
                                continue; /* don't go back: neighbors are in order of ascending ord. numbers */
                            }
                            pEndp2 = pBNS->vert + endpoint2;
                            if (!( pEndp2->type & BNS_VERT_TYPE_ENDPOINT ))
                            {
                                continue;
                            }
                            etg2 = pBNS->edge + pVA[endpoint2].nTautGroupEdge - 1;
                            if (!etg2->flow || ( etg2->neighbor12 ^ endpoint2 ) != vtg1)
                            {
                                continue;
                            }
                            /* we have found the path:
                                              Endp1                                Endp1
                                       etg1 //     \ ecp1                   etg1 /     \\ ecp1
                                  etg0     //       \                  etg0     /       \\
                             Endp0-----tg1           Centp  -->   Endp0=====tg1           Centp
                              ^            \\       /                           \\       /
                      radical |        etg2 \\     / ecp2                   etg2 \\     / ecp2
                                              Endp2                                Endp2
                            */

                            /* compare centerpoints */
                            if (!pCentp_found ||
                                 /* try to avoid carbons */
                                (( pVA[centerpoint].cNumValenceElectrons != 4 ||
                                    pVA[centerpoint].cPeriodicRowNumber != 1 ) &&
                                 pVA[centerpoint_found].cNumValenceElectrons == 4 &&
                                 pVA[centerpoint_found].cPeriodicRowNumber == 1) ||
                                 /* try a better non-carbon */
                                 (( pVA[centerpoint].cNumValenceElectrons != 4 ||
                                     pVA[centerpoint].cPeriodicRowNumber != 1 ) &&
                                     ( at[centerpoint].valence > at[centerpoint_found].valence ||
                                         (at[centerpoint].valence == at[centerpoint_found].valence &&
                                         at[centerpoint].el_number > at[centerpoint_found].el_number) ))) /* djb-rwth: addressing LLVM warnings */
                            {

                                pCentp_found = pCentp;
                                etg1_found = etg1;
                                ecp1_found = ecp1;
                                centerpoint_found = centerpoint;
                                break;
                            }
                        }
                    }
                }
            }
            if (pCentp_found)
            {
                /* ---- (1) */
                etg0->flow++;
                pEndp0->st_edge.flow++;
                /* ---- (2) */
                etg1_found->flow--;
                /* ---- (3) */
                ecp1_found->flow++;
                /* ---- (4) */
                pCentp_found->st_edge.flow++;
                pCentp_found->st_edge.cap++;

                pBNS->tot_st_flow += 2;
                pBNS->tot_st_cap += 1;
                pCentp_found = NULL;
                num_fixes++;
                tot_num_fixes++;   /* #1 Mob-H */
                continue;
            }

            /* 2nd attempt: increment flow in centerpoint---radical_endpint edge */
            if (i < num_endpoints)
            {
                /* tautomeric endpoint found; traverse its t-group edges */
                for (j = 0; j < num_endpoints; j++)
                {
                    if (i == j)
                    {
                        continue; /* avoid the found radical endpoint */
                    }
                    etg1 = pBNS->edge + ptg1->iedge[j];
                    endpoint1 = etg1->neighbor12 ^ vtg1;
                    pEndp1 = pBNS->vert + endpoint1;     /* another endpoint */
                    if (pEndp1->st_edge.cap > pEndp1->st_edge.flow)
                    {
                        continue; /* one more radical-endpoint! What is going on here??? */
                    }
                    if (!etg1->flow)
                    {
                        continue; /* avoid enpoints that do not have an attachment */
                    }
                    if (!( pEndp1->type & BNS_VERT_TYPE_ENDPOINT ))
                    {
                        continue; /* should not happen */
                    }
                    /* traverse endpoint1 edges to find the edge connecting it to the centerpoint */
                    for (k = 0; k < at2[endpoint1].valence; k++)
                    {
                        ecp1 = pBNS->edge + pEndp1->iedge[k];
                        if (ecp1->flow)
                        {
                            continue;
                        }
                        centerpoint = ecp1->neighbor12 ^ endpoint1;
                        pCentp = pBNS->vert + centerpoint;
                        if (pCentp->type & BNS_VERT_TYPE_ENDPOINT)
                        {
                            continue; /* do not set another endpoint's valence = an unusual value */
                        }

                        /* traverse centerpoint edges to find edge connecting it to the endpoint0 */
                        ecp2 = NULL;
                        pEndp2 = NULL;
                        for (n = 0; n < at2[centerpoint].valence; n++)
                        {
                            ecp0 = pBNS->edge + pCentp->iedge[n];
                            if (ecp0->flow)
                            {
                                endpoint2 = ecp0->neighbor12 ^ centerpoint;
                                if (( pBNS->vert[endpoint2].type & BNS_VERT_TYPE_ENDPOINT ))
                                {
                                    continue; /* ignore endpoint2 if it is tautomeric endpoint */
                                }
                                /* check whether ecp0 is stereogenic: if it is then we cannot decrement its flow */
                                for (m = 0; m < MAX_NUM_STEREO_BONDS && at[centerpoint].sb_parity[m]; m++)
                                {
                                    if (at[centerpoint].sb_ord[m] == n)
                                    {
                                        endpoint2 = NO_VERTEX;
                                        break;
                                    }
                                }
                                if (endpoint2 == NO_VERTEX)
                                {
                                    continue;
                                }
                                pEndp2 = pBNS->vert + endpoint2;  /* found */
                                ecp2 = ecp0;
                                break;
                            }
                        }
                        for (n = 0; n < at[centerpoint].valence; n++)
                        {
                            ecp0 = pBNS->edge + pCentp->iedge[n];
                            if (ecp0->flow)
                            {
                                continue;
                            }
                            if (endpoint0 != ( ecp0->neighbor12 ^ centerpoint ))
                            {
                                continue;
                            }
                            /* Found:
                                              Endp2(not endpoint)           Endp2(not radical)
                                               ||                             |
                                               ||ecp2                         |ecp2
                                          ecp0 ||  ecp1                 ecp0  |  ecp1
                                     Endp0----Centp----Endp1       Endp0====Centp----Endp1
                                      ^  \             /      -->      \             /
                              radical |   \           /                 \           /
                                           \         /                   \         /
                                       etg0 \       / etg1           etg0 \       / etg1
                                             \     /                       \     /
                                               tg1                           tg1

                             */

                            /* compare centerpoints */
                            if (!pCentp_found ||
                                 /* try to avoid carbons */
                                (( pVA[centerpoint].cNumValenceElectrons != 4 ||
                                    pVA[centerpoint].cPeriodicRowNumber != 1 ) &&
                                 pVA[centerpoint_found].cNumValenceElectrons == 4 &&
                                 pVA[centerpoint_found].cPeriodicRowNumber == 1) ||
                                 /* try a better non-carbon */
                                 (( pVA[centerpoint].cNumValenceElectrons != 4 ||
                                     pVA[centerpoint].cPeriodicRowNumber != 1 ) &&
                                     ( at[centerpoint].valence > at[centerpoint_found].valence ||
                                         (at[centerpoint].valence == at[centerpoint_found].valence &&
                                         at[centerpoint].el_number > at[centerpoint_found].el_number)) )) /* djb-rwth: addressing LLVM warnings */
                            {

                                pCentp_found = pCentp;
                                etg1_found = etg1;
                                ecp0_found = ecp0;
                                centerpoint_found = centerpoint;
                                pEndp2_found = pEndp2;
                                ecp2_found = ecp2;
                                break;
                            }
                        }
                    }
                }
            }
            if (pCentp_found)
            {
                ecp0_found->flow++;
                if (ecp0_found->cap < ecp0_found->flow)
                {
                    ecp0_found->cap = ecp0_found->flow;
                }
                pEndp0->st_edge.flow++;
                if (pEndp2_found && ecp2_found)
                {
                    ecp2_found->flow--;
                    pEndp2_found->st_edge.flow--;
                }
                else
                {
                    /* Endp2 not found */
                    pCentp_found->st_edge.flow++;
                    pCentp_found->st_edge.cap++;
                    pBNS->tot_st_flow += 2; /* radical elimination */
                    pBNS->tot_st_cap += 1;
                }

                pCentp_found = NULL;
                num_fixes++;
                tot_num_fixes++;      /* #2 Mob-H */
                continue;
            }
            /* 3rd attempt: find =C= and move radical to it */
            if (i < num_endpoints)
            {
                int jj, delta, bNotFixed = 1;
                Vertex     vPathStart, vPathEnd, v1, v2;
                int        nPathLen, nDeltaH, nDeltaCharge, nNumVisitedAtoms;
                for (jj = 0; jj < num_at && bNotFixed; jj++)
                {
                    if (at2[i].endpoint)
                    {
                        continue;
                    }
                    if (2 == at2[jj].valence && pBNS->vert[jj].st_edge.cap == pBNS->vert[jj].st_edge.flow &&
                         4 == pVA[jj].cNumValenceElectrons &&
                         !( ecp0 = pBNS->edge + pBNS->vert[jj].iedge[0] )->forbidden &&
                         !( ecp1 = pBNS->edge + pBNS->vert[jj].iedge[1] )->forbidden &&
                         1 == ecp0->flow && 1 == ecp1->flow &&
                         !at2[(int) at2[i].neighbor[0]].sb_parity[0] &&
                         !at2[(int) at2[i].neighbor[1]].sb_parity[0])
                    {
                        /* found =C=; make a radical and try to cancel the two radicals */
                        k = ecp0->neighbor12 ^ jj;
                        if (at2[k].endpoint)
                        {
                            ecp0 = ecp1;
                            k = ecp0->neighbor12 ^ jj;
                            if (at2[k].endpoint)
                            {
                                continue;
                            }
                        }
                        delta = 1;
                        /* decrement C valence */
                        pBNS->vert[jj].st_edge.flow -= delta;
                        pBNS->vert[jj].st_edge.cap -= delta;
                        /* decrement bond order */
                        ecp0->flow -= delta;
                        /* reflect the changes in at2[k] to make it a radical */
                        pBNS->vert[k].st_edge.flow -= delta;
                        pBNS->tot_st_cap -= delta;
                        pBNS->tot_st_flow -= 2 * delta;

                        v1 = endpoint0;
                        v2 = k;

                        ret2 = RunBnsTestOnce( pBNS, pBD, pVA, &vPathStart, &vPathEnd, &nPathLen,
                                              &nDeltaH, &nDeltaCharge, &nNumVisitedAtoms );

                        if (ret2 == 1 && ( (vPathEnd == v1 && vPathStart == v2) ||
                            (vPathEnd == v2 && vPathStart == v1) ) && nDeltaCharge == 0) /* djb-rwth: addressing LLVM warnings */
                        {
                            ret2 = RunBnsRestoreOnce( pBNS, pBD, pVA, pTCGroups );
                            if (ret2 > 0)
                            {
                                num_fixes++;
                                tot_num_fixes++;   /* #3 Mob-H */
                                pBNS->vert[jj].st_edge.cap += delta; /* create radical on =C- */
                                pBNS->tot_st_cap += delta;
                                pCentp_found = NULL;
                                /* djb-rwth: removing redundant code */
                                break;
                            }
                        }
                        else
                        {
                            /* failed */
                            pBNS->vert[jj].st_edge.flow += delta;
                            pBNS->vert[jj].st_edge.cap += delta;
                            /* decrement bond order */
                            ecp0->flow += delta;
                            /* reflect the changes in at2[k] to make it a radical */
                            pBNS->vert[k].st_edge.flow += delta;
                            pBNS->tot_st_cap += delta;
                            pBNS->tot_st_flow += 2 * delta;
                        }
                        if (ret2 < 0)
                        {
                            ret = ret2;
                            goto exit_function;
                        }
                    }
                }
            }
        }
        if (!num_fixes)
        {
            break;
        }
    }
    ret = tot_num_fixes;

exit_function:
    pStruct->at = at;
    memcpy(at2, at, len_at * sizeof(at2[0]));
    return ret;
}


/****************************************************************************
 Find and eliminate cases when Mobile H endpoint has radical on it
(typical for wrong P(VI)(=O)3OH)
****************************************************************************/
int RemoveRadFromMobileHEndpointFixH( BN_STRUCT *pBNS,
                                      BN_DATA *pBD,
                                      StrFromINChI *pStruct,
                                      inp_ATOM *at,
                                      inp_ATOM *at2,
                                      VAL_AT *pVA,
                                      ALL_TC_GROUPS *pTCGroups,
                                      int *pnNumRunBNS,
                                      int *pnTotalDelta,
                                      int forbidden_edge_mask )
{
#define IS_C(x) (NO_VERTEX != x && pVA[x].cNumValenceElectrons == 4 && pVA[x].cPeriodicRowNumber == 1)
    int i, num_fixes, tot_num_fixes = 0;

    int ret2, ret;
    int num_at = pStruct->num_atoms;
    int num_deleted_H = pStruct->num_deleted_H;
    int len_at = num_at + num_deleted_H;
    int inv_forbidden_edge_mask = ~forbidden_edge_mask;
    EDGE_LIST ChargeEdgeList, BondEdgeList;
    int         itg, j, k, n, m; /* djb-rwth: removing redundant variables */
    Vertex      endpoint0 = NO_VERTEX, endpoint1, endpoint2 = NO_VERTEX, centerpoint;
    Vertex      centerpoint_found = NO_VERTEX, endpoint2_found = NO_VERTEX;
    BNS_VERTEX *pEndp0 = NULL, *pEndp1, *pEndp2, *pCentp, *pCentp_found, *pEndp2_found = NULL;
    BNS_EDGE   *ecp0, *ecp1, *ecp2, *ecp0_found = NULL, *ecp1_found = NULL, *ecp2_found = NULL;
    int         num_endpoints; /* djb-rwth: removing redundant variables */

    ret = 0;

    if (pStruct->iMobileH != TAUT_NON)
        return ret;

    AllocEdgeList( &ChargeEdgeList, EDGE_LIST_CLEAR );
    AllocEdgeList( &BondEdgeList, EDGE_LIST_CLEAR );

    memcpy(at2, at, len_at * sizeof(at2[0]));
    pStruct->at = at2;
    ret2 = CopyBnsToAtom( pStruct, pBNS, pVA, pTCGroups, 1 );
    if (ret2 < 0)
    {
        ret = ret2;
        goto exit_function;
    }
    while (pBNS->tot_st_cap > pBNS->tot_st_flow && pStruct->ti.num_t_groups)
    {
        int iEndpoint = 0;
        num_fixes = 0;
        for (itg = 0; itg < pStruct->ti.num_t_groups; iEndpoint += num_endpoints, itg++)
        {
            pCentp_found = NULL;
            /* djb-rwth: removing redundant code */
            num_endpoints = pStruct->ti.t_group[itg].nNumEndpoints;
            for (i = 0; i < num_endpoints; i++)
            {
                endpoint0 = pStruct->ti.nEndpointAtomNumber[iEndpoint + i];
                pEndp0 = pBNS->vert + endpoint0;  /* taut endpoint vertex (possible location of mobile H */
                if (pEndp0->st_edge.cap > pEndp0->st_edge.flow)
                {
                    /* radical endpoint1 has been detected */
                    /* find a 1-3 centerpoint that has two or more endpoints */
                    /* connected to the t-group vertex by edges with flow>0 and */
                    /* to the centerpoint by edges with flow = 0 */
                    /* after that: (1) increment etg1 flow to eliminate radical */
                    /* (2) increment flow on one of the two other edges to the t-group */
                    /* (3) increment st_cap on the found centerpoint */
                    /* (4) rerun the BNS and re-create the structure */
                    break;
                }
            }

            /* 2nd attempt: increment flow in centerpoint---radical_endpoint edge */
            pCentp_found = NULL;
            if (i < num_endpoints)
            {
                /* tautomeric endpoint found; traverse its t-group edges */
                for (j = 0; j < num_endpoints; j++)
                {
                    if (i == j)
                    {
                        continue; /* avoid the found radical endpoint */
                    }
                    endpoint1 = pStruct->ti.nEndpointAtomNumber[iEndpoint + j];
                    pEndp1 = pBNS->vert + endpoint1;     /* another endpoint */

                    if (pEndp1->st_edge.cap > pEndp1->st_edge.flow)
                    {
                        continue; /* one more radical-endpoint! What is going on here??? */
                    }
                    if (!at2[endpoint1].num_H && at2[endpoint1].charge != -1)
                    {
                        continue; /* avoid enpoints that do not have an attachment */
                    }
                    if (!pStruct->endpoint[endpoint1])
                    {
                        continue; /* should not happen */
                    }
                    /* traverse endpoint1 edges to find the edge connecting it to the centerpoint */
                    for (k = 0; k < pEndp1->num_adj_edges; k++)
                    {
                        ecp1 = pBNS->edge + pEndp1->iedge[k];
                        if (ecp1->flow)
                        {
                            continue;
                        }
                        centerpoint = ecp1->neighbor12 ^ endpoint1;
                        if (centerpoint >= pBNS->num_atoms)
                        {
                            break; /* no more edges to atoms */
                        }
                        pCentp = pBNS->vert + centerpoint;
                        if (pStruct->endpoint[centerpoint])
                        {
                            continue; /* do not set another endpoint's valence = an unusual value */
                        }
                        /* traverse centerpoint edges to find edge connecting it to the endpoint0 */
                        /* 1. Find a double bond to an endpoint */
                        ecp2 = NULL;
                        pEndp2 = NULL;
                        for (n = 0; n < at2[centerpoint].valence; n++) /* djb-rwth: removing redundant code */
                        {
                            ecp0 = pBNS->edge + pCentp->iedge[n];
                            if (ecp0->flow)
                            {
                                endpoint2 = ecp0->neighbor12 ^ centerpoint;
                                if (pStruct->endpoint[endpoint2] /* ??? */)
                                {
                                    continue;
                                }
                                /* check whether ecp0 is stereogenic: if it is then we cannot decrement its flow */
                                for (m = 0; m < MAX_NUM_STEREO_BONDS && at[centerpoint].sb_parity[m]; m++)
                                {
                                    if (at[centerpoint].sb_ord[m] == n)
                                    {
                                        endpoint2 = NO_VERTEX;
                                        break;
                                    }
                                }
                                if (endpoint2 == NO_VERTEX)
                                {
                                    continue;
                                }
                                pEndp2 = pBNS->vert + endpoint2;
                                ecp2 = ecp0;
                                break;
                            }
                        }
                        if (!ecp2)
                        {
                            continue;
                        }
                        /* 2. Find a single bond to an endpoint0 */
                        for (n = 0; n < at2[centerpoint].valence; n++) /* djb-rwth: removing redundant code */
                        {
                            ecp0 = pBNS->edge + pCentp->iedge[n];
                            if (ecp0->flow)
                            {
                                continue;
                            }
                            if (endpoint0 != ( ecp0->neighbor12 ^ centerpoint ))
                            {
                                continue;
                            }
                            /* Found:
                                              Endp2                         Endp2(not radical)
                                               ||                             |
                                               ||ecp2                         |ecp2
                                          ecp0 ||  ecp1                 ecp0  |  ecp1
                                     Endp0----Centp----Endp1       Endp0====Centp----Endp1
                                      ^  \             /      -->      \             /
                              radical |   \           /                 \           /
                                           \         /                   \         /
                                       etg0 \       / etg1           etg0 \       / etg1
                                             \     /                       \     /
                                               tg1                           tg1

                             */

                            /* compare centerpoints */
                            if (!pCentp_found ||
                                 /* try to avoid carbons */
                                (( pVA[centerpoint].cNumValenceElectrons != 4 ||
                                    pVA[centerpoint].cPeriodicRowNumber != 1 ) &&
                                 pVA[centerpoint_found].cNumValenceElectrons == 4 &&
                                 pVA[centerpoint_found].cPeriodicRowNumber == 1) ||
                                 /* try a better non-carbon */
                                 (( pVA[centerpoint].cNumValenceElectrons != 4 ||
                                     pVA[centerpoint].cPeriodicRowNumber != 1 ) &&
                                     ( at[centerpoint].valence > at[centerpoint_found].valence ||
                                         (at[centerpoint].valence == at[centerpoint_found].valence &&
                                         at[centerpoint].el_number > at[centerpoint_found].el_number)) )) /* djb-rwth: addressing LLVM warnings */
                            {

                                pCentp_found = pCentp;
                                ecp0_found = ecp0;
                                centerpoint_found = centerpoint;
                                pEndp2_found = pEndp2;
                                ecp2_found = ecp2;
                                break;
                            }
                        }
                    }
                }
            }
            /* decrement st_flow, st_cap on Endp2; decrement flow on ecp2; decrement st_flow on Centp */
            /* result: radicals on Endp0 and Centp => run BNS */
            if (pCentp_found)
            {
                /* make ecp0 a double bond, make ecp2 a single bond, remove radical */
                ecp0_found->flow++;
                if (ecp0_found->cap < ecp0_found->flow)
                {
                    ecp0_found->cap = ecp0_found->flow;
                }
                pEndp0->st_edge.flow++;
                if (pEndp2_found && ecp2_found)
                {
                    ecp2_found->flow--;
                    pEndp2_found->st_edge.flow--;
                }
                else
                {
                             /* Endp2 not found: only make ecp0 a double bond */
                    pCentp_found->st_edge.flow++;
                    pCentp_found->st_edge.cap++;
                    pBNS->tot_st_flow += 2; /* radical elimination */
                    pBNS->tot_st_cap += 1;
                }

                pCentp_found = NULL;
                num_fixes++;    /* #2 */
                tot_num_fixes++;
                continue;
            }
            /* 1st attempt */
            pCentp_found = NULL;
            if (i < num_endpoints)
            {
                /* tautomeric endpoint found; traverse its t-group edges */
                for (j = 0; j < num_endpoints; j++)
                {
                    if (i == j)
                    {
                        continue; /* avoid the found radical endpoint */
                    }
                    endpoint1 = pStruct->ti.nEndpointAtomNumber[iEndpoint + j];
                    pEndp1 = pBNS->vert + endpoint1;     /* another endpoint */
                    if (pEndp1->st_edge.cap > pEndp1->st_edge.flow)
                    {
                        continue; /* one more radical-endpoint! What is going on here??? */
                    }
                    if (!at2[endpoint1].num_H && at2[endpoint1].charge != -1)
                    {
                        continue; /* avoid enpoints that do not have an attachment */
                    }
                    if (!pStruct->endpoint[endpoint1])
                    {
                        continue; /* should not happen */
                    }
                    /* traverse endpoint1 edges to find the edge connecting it to the centerpoint */
                    for (k = 0; k < pEndp1->num_adj_edges; k++)
                    {
                        ecp1 = pBNS->edge + pEndp1->iedge[k];
                        if (ecp1->flow)
                        {
                            continue;
                        }
                        centerpoint = ecp1->neighbor12 ^ endpoint1;
                        if (centerpoint >= pBNS->num_atoms)
                        {
                            break;
                        }
                        pCentp = pBNS->vert + centerpoint;
                        /* traverse centerpoint edges to find the 2nd endpoint */
                        for (n = 0; n < pCentp->num_adj_edges; n++) /* djb-rwth: removing redundant code */
                        {
                            ecp2 = pBNS->edge + pCentp->iedge[n];
                            if (ecp2->flow)
                            {
                                continue;
                            }
                            endpoint2 = ecp2->neighbor12 ^ centerpoint;
                            if (endpoint2 >= pBNS->num_atoms)
                            {
                                break;
                            }
                            if (!pStruct->endpoint[endpoint2])
                            {
                                continue;
                            }
                            /* djb-rwth: removing redundant code */

                            if (at2[endpoint2].num_H || at2[endpoint1].charge == -1)
                            {
                                continue;
                            }

                            /* we have found the path:

                            Endp1 has no attachments, Endp2 has.

                                              Endp1                                Endp1
                                       etg1 //     \ ecp1                   etg1 /     \\ ecp1
                                  etg0     //       \                  etg0     /       \\
                             Endp0-----tg1           Centp  -->   Endp0=====tg1           Centp
                              ^            \\       /                           \\       /
                      radical |        etg2 \\     / ecp2                   etg2 \\     / ecp2
                                              Endp2                                Endp2
                            */

                            /* compare centerpoints */
                            if (!pCentp_found ||
                                 /* try to avoid carbons */
                                (( pVA[centerpoint].cNumValenceElectrons != 4 ||
                                    pVA[centerpoint].cPeriodicRowNumber != 1 ) &&
                                 pVA[centerpoint_found].cNumValenceElectrons == 4 &&
                                 pVA[centerpoint_found].cPeriodicRowNumber == 1) ||
                                 /* try a better non-carbon */
                                 (( pVA[centerpoint].cNumValenceElectrons != 4 ||
                                     pVA[centerpoint].cPeriodicRowNumber != 1 ) &&
                                     ( at[centerpoint].valence > at[centerpoint_found].valence ||
                                         (at[centerpoint].valence == at[centerpoint_found].valence &&
                                         at[centerpoint].el_number > at[centerpoint_found].el_number)) )) /* djb-rwth: addressing LLVM warnings */
                            {

                                pCentp_found = pCentp;
                                ecp1_found = ecp1;
                                centerpoint_found = centerpoint;
                                break;
                            }
                        }
                    }
                }
            }
            if (pCentp_found)
            {
                /* create a new radical at the centerpoint and try to cancel them */
                int delta = 1, ret3;
                Vertex     vPathStart, vPathEnd, v1, v2;
                int        nPathLen, nDeltaH, nDeltaCharge, nNumVisitedAtoms;

                pCentp_found->st_edge.cap += delta;
                pBNS->tot_st_cap += delta;

                v1 = (int) ( pCentp_found - pBNS->vert );
                v2 = (int) ( pEndp0 - pBNS->vert );

                ret3 = RunBnsTestOnce( pBNS, pBD, pVA, &vPathStart, &vPathEnd, &nPathLen,
                                      &nDeltaH, &nDeltaCharge, &nNumVisitedAtoms );

                if (ret3 == 1 && ( (vPathEnd == v1 && vPathStart == v2) ||
                    (vPathEnd == v2 && vPathStart == v1) ) && nDeltaCharge % 2 == 0) /* djb-rwth: addressing LLVM warnings */
                {
                    ret3 = RunBnsRestoreOnce( pBNS, pBD, pVA, pTCGroups );
                    if (ret3 > 0)
                    {
                        num_fixes++;
                        tot_num_fixes++;   /* #1 */
                        pCentp_found = NULL;
                        continue;
                    }
                }
                else
                {
                    pCentp_found->st_edge.cap -= delta;
                    pBNS->tot_st_cap -= delta;
                }
                if (ret3 < 0)
                {
                    ret = ret3;
                    goto exit_function;
                }
            }
            /*----------------------------------------------------------------------------------------
               3rd attempt:                                                         add radical to keep
              ==============           u,f=>unfixed, fixed edges                    (N electrons)%2
                        (-)                       (-)                      (-)          |
                     e0/  \\ e1          =>     u/  \\u            =>     //  \         v
                      /    \\ ecp1 ecp2         /    \\   u    f         //    \
                  C--X*     Y(-)--C==Z      C--X*     Y(-)--C*--Z      --X(-)   Y===C---Z*
                    rad.    endp     not      rad.   endp  rad not      rad.   endp    not
                   Endp0   Endp1     endp     endp         to  endp     endp           endp
                                    Endp2                cancel

               Note: endpoints X and Y may belong to different t-groups
             ----------------------------------------------------------------------------------------*/
            pCentp_found = NULL;
            if (i < num_endpoints)
            {
                int  e0, e1;
                if (( e0 = pVA[endpoint0].nCMinusGroupEdge - 1 ) < 0 || pBNS->edge[e0].forbidden)
                {
                    continue; /* no negative charge on Endp0 is possible */
                }
                /* a radical-tautomeric endpoint found; traverse all endpoints */
                for (j = 0; j < pStruct->ti.nNumEndpoints; j++)
                {
                    if (iEndpoint + i == j)
                    {
                        continue; /* avoid the found radical endpoint */
                    }

                    endpoint1 = pStruct->ti.nEndpointAtomNumber[j];
                    pEndp1 = pBNS->vert + endpoint1;     /* another endpoint */

                    if (pEndp1->st_edge.cap > pEndp1->st_edge.flow)
                    {
                        continue; /* one more radical-endpoint! What is going on here??? */
                    }
                    if (( ( e1 = pVA[endpoint1].nCMinusGroupEdge - 1 ) < 0 || !pBNS->edge[e1].flow ) || pBNS->edge[e1].forbidden)
                    {
                        continue; /* no negative charge on Endp1 */
                    }
                    if (!pStruct->endpoint[endpoint1])
                    {
                        continue; /* should not happen */
                    }
                    /* traverse endpoint1 edges to find the edge connecting it to the centerpoint */
                    for (k = 0; k < pEndp1->num_adj_edges; k++)
                    {
                        ecp1 = pBNS->edge + pEndp1->iedge[k];   /* e1C */
                        if (ecp1->flow || ecp1->forbidden)
                        {
                            continue;
                        }
                        centerpoint = ecp1->neighbor12 ^ endpoint1;
                        if (centerpoint >= pBNS->num_atoms)
                        {
                            break; /* no more edges to atoms */
                        }
                        pCentp = pBNS->vert + centerpoint;
                        if (pStruct->endpoint[centerpoint])
                        {
                            continue; /* do not set another endpoint's valence = an unusual value */
                        }
                        /* traverse centerpoint edges to find edge connecting it to the endpoint0 */
                        /* 1. Find a double bond to a not endpoint */
                        ecp2 = NULL;
                        pEndp2 = NULL;
                        for (n = 0; n < pCentp->num_adj_edges; n++) /* djb-rwth: removing redundant variables/code */
                        {
                            ecp0 = pBNS->edge + pCentp->iedge[n];
                            if (ecp0->flow && !ecp0->forbidden)
                            {
                                endpoint2 = ecp0->neighbor12 ^ centerpoint;
                                if (endpoint2 >= pBNS->num_atoms || pStruct->endpoint[endpoint2])
                                {
                                    continue;
                                }
                                /* check whether ecp0 is stereogenic: if it is then we cannot decrement its flow */
                                for (m = 0; m < MAX_NUM_STEREO_BONDS && at[centerpoint].sb_parity[m]; m++)
                                {
                                    if (at[centerpoint].sb_ord[m] == n)
                                    {
                                        endpoint2 = NO_VERTEX;
                                        break;
                                    }
                                }
                                if (endpoint2 == NO_VERTEX)
                                {
                                    continue;
                                }
                                /* djb-rwth: removing redundant code */
                                ecp2 = ecp0;           /* e2C */
                                break;
                            }
                        }
                        if (!ecp2)
                        {
                            continue;
                        }
                        /* compare centerpoints */
                        if (!pCentp_found ||
                             /* try to find carbons */
                             (!IS_C( endpoint2_found ) && IS_C( endpoint2 )) ||
                             (IS_C( endpoint2_found ) && IS_C( endpoint2 ) &&
                             !IS_C( centerpoint_found ) && IS_C( centerpoint ))) /* djb-rwth: addressing LLVM warnings */
                        {

                            pCentp_found = pCentp;
                            centerpoint_found = centerpoint;
                            endpoint2_found = endpoint2;
                            ecp2_found = ecp2;
                            ecp1_found = ecp1;
                            ecp0_found = pBNS->edge + e0;
                            break;
                        }
                    }
                }
            }
            /* decrement st_flow, st_cap on Endp2; decrement flow on ecp2; decrement st_flow on Centp */
            /* result: radicals on Endp0 and Centp => run BNS */
            if (pCentp_found)
            {
                Vertex     vPathStart, vPathEnd, v1, v2;
                int        nPathLen, nDeltaH, nDeltaCharge, nNumVisitedAtoms;
                int        delta;

                Vertex    vEndp0 = ecp0_found->neighbor1;
                Vertex    vEndp1 = ecp1_found->neighbor12 ^ centerpoint_found;
                Vertex    vEndp2 = ecp2_found->neighbor12 ^ centerpoint_found;
                BNS_EDGE *pe0 = ecp0_found;
                BNS_EDGE *pe1 = pBNS->edge + ( (long long)pVA[vEndp1].nCMinusGroupEdge - 1 ); /* djb-rwth: cast operator added */
                /* djb-rwth: removing redundant code */
                pEndp2 = pBNS->vert + vEndp2;
                pCentp = pCentp_found;
                if (!ChargeEdgeList.num_alloc)
                {
                    for (n = 0; n < pStruct->num_atoms; n++)
                    {
                        if (( k = pVA[n].nCMinusGroupEdge ) >= 0 && !pBNS->edge[k].forbidden &&
                            ( ret = AddToEdgeList( &ChargeEdgeList, k, pStruct->num_atoms ) ))
                        {
                            goto exit_function;
                        }
                        if (( k = pVA[n].nCPlusGroupEdge ) >= 0 && !pBNS->edge[k].forbidden &&
                            ( ret = AddToEdgeList( &ChargeEdgeList, k, pStruct->num_atoms ) ))
                        {
                            goto exit_function;
                        }
                    }
                }
                if (!BondEdgeList.num_alloc)
                {
                    for (n = 0; n < pBNS->num_bonds; n++)
                    {
                        if (( ret = AddToEdgeList( &BondEdgeList, n, pBNS->num_bonds ) ))
                        {
                            goto exit_function;
                        }
                    }
                }
                /* fix all bonds and charges */
                SetForbiddenEdgeMask( pBNS, &ChargeEdgeList, forbidden_edge_mask );
                SetForbiddenEdgeMask( pBNS, &BondEdgeList, forbidden_edge_mask );
                /* prepare flow for testing */
                delta = 1;
                ecp2_found->flow -= delta;
                pCentp->st_edge.flow -= delta;
                pEndp2->st_edge.flow -= delta;
                pBNS->tot_st_flow -= 2 * delta;
                /* unfix edges to be changed */
                pe0->forbidden &= inv_forbidden_edge_mask;
                pe1->forbidden &= inv_forbidden_edge_mask;
                ecp1_found->forbidden &= inv_forbidden_edge_mask;

                pBNS->tot_st_cap += delta;

                v1 = vEndp0;
                v2 = centerpoint_found;
                ret2 = RunBnsTestOnce( pBNS, pBD, pVA, &vPathStart, &vPathEnd, &nPathLen,
                                      &nDeltaH, &nDeltaCharge, &nNumVisitedAtoms );

                if (ret2 == 1 && ( (vPathEnd == v1 && vPathStart == v2) ||
                    (vPathEnd == v2 && vPathStart == v1) ) && nDeltaCharge == 0) /* djb-rwth: addressing LLVM warnings */
                {
                    ret2 = RunBnsRestoreOnce( pBNS, pBD, pVA, pTCGroups );
                    if (ret2 > 0)
                    {
                        num_fixes++;
                        tot_num_fixes++; /* #3 */
                        pCentp_found = NULL;
                    }
                }
                else
                {
                    /* roll back */
                    ecp2_found->flow += delta;
                    pCentp->st_edge.flow += delta;
                    pEndp2->st_edge.flow += delta;
                    pBNS->tot_st_flow += 2 * delta;
                }
                RemoveForbiddenEdgeMask( pBNS, &ChargeEdgeList, forbidden_edge_mask );
                RemoveForbiddenEdgeMask( pBNS, &BondEdgeList, forbidden_edge_mask );
                if (ret2 < 0)
                {
                    ret = ret2;
                    goto exit_function;
                }
                if (!pCentp_found)
                    continue;
            }
        }
        if (!num_fixes)
        {
            break;
        }
    }

    /************ again ***********************************************************/
    while (pBNS->tot_st_cap > pBNS->tot_st_flow && pStruct->ti.num_t_groups)
    {
        int iEndpoint = 0;
        num_fixes = 0;
        for (itg = 0; itg < pStruct->ti.num_t_groups; iEndpoint += num_endpoints, itg++)
        {
            pCentp_found = NULL;
            /* djb-rwth: removing redundant code */
            num_endpoints = pStruct->ti.t_group[itg].nNumEndpoints;
            for (i = 0; i < num_endpoints; i++)
            {
                endpoint0 = pStruct->ti.nEndpointAtomNumber[iEndpoint + i];
                pEndp0 = pBNS->vert + endpoint0;  /* taut endpoint vertex (possible location of mobile H */
                if (pEndp0->st_edge.cap > pEndp0->st_edge.flow)
                {
                    /* radical endpoint1 has been detected */
                    /* find a 1-3 centerpoint that has two or more endpoints */
                    /* connected to the t-group vertex by edges with flow>0 and */
                    /* to the centerpoint by edges with flow = 0 */
                    /* after that: (1) increment etg1 flow to eliminate radical */
                    /* (2) increment flow on one of the two other edges to the t-group */
                    /* (3) increment st_cap on the found centerpoint */
                    /* (4) rerun the BNS and re-create the structure */
                    break;
                }
            }
            /* 4th attempt */
            if (i < num_endpoints)
            {
                /* tautomeric endpoint found; traverse its t-group edges */
                pEndp2_found = NULL;
                for (j = 0; j < pEndp0->num_adj_edges; j++)
                {
                    ecp0 = pBNS->edge + pEndp0->iedge[j];
                    centerpoint = ecp0->neighbor12 ^ endpoint0;
                    if (centerpoint >= pBNS->num_atoms || ecp0->flow || pStruct->endpoint[centerpoint])
                    {
                        continue; /* ignore non-single bonds, orig. InChI endpoints, and fictitious atoms */
                    }
                    pCentp = pBNS->vert + centerpoint;
                    for (k = 0; k < pCentp->num_adj_edges; k++)
                    {
                        ecp1 = pBNS->edge + pCentp->iedge[k];
                        endpoint1 = ecp1->neighbor12 ^ centerpoint;
                        if (endpoint1 >= pBNS->num_atoms || !ecp1->flow || pStruct->endpoint[endpoint1])
                        {
                            continue; /* ignore single bonds, orig. InChI endpoints, and fictitious atoms */
                        }
                        pEndp1 = pBNS->vert + endpoint1;
                        if (endpoint1 == endpoint0 || pEndp1->st_edge.cap != pEndp1->st_edge.flow)
                        {
                            continue; /* ignore radicals */
                        }
                        if (!pEndp2_found ||
                             /* try to find carbons */
                             (!IS_C( endpoint2_found ) && IS_C( endpoint1 )) ||
                             (IS_C( endpoint2_found ) && IS_C( endpoint1 ) &&
                             !IS_C( centerpoint_found ) && IS_C( centerpoint ))) /* djb-rwth: addressing LLVM warning */
                        {
                            pEndp2_found = pEndp1;
                            /* djb-rwth: removing redundant code */
                            endpoint2_found = endpoint1;
                            centerpoint_found = centerpoint;
                            ecp1_found = ecp0;
                            ecp2_found = ecp1;
                        }
                    }
                }
                if (pEndp2_found)
                {
                    /* move radical from pEndp0 to pEndp2 */
                    pEndp0->st_edge.flow++;
                    ecp1_found->flow++;
                    ecp2_found->flow--;
                    pEndp2_found->st_edge.flow--;
                    pEndp2_found = NULL;
                    pCentp_found = NULL;
                    num_fixes++;    /* #4 */
                    tot_num_fixes++;
                    continue;
                }
            }
        }
        if (!num_fixes)
        {
            break;
        }
    }

    ret = tot_num_fixes;

exit_function:
    AllocEdgeList( &ChargeEdgeList, EDGE_LIST_FREE );
    AllocEdgeList( &BondEdgeList, EDGE_LIST_FREE );

    pStruct->at = at;
    memcpy(at2, at, len_at * sizeof(at2[0]));

    return ret;
#undef IS_C
}


/****************************************************************************
 move (+) charges to >N- and other centerpoints
****************************************************************************/
int MoveChargeToMakeCenerpoints( BN_STRUCT *pBNS,
                                BN_DATA *pBD,
                                StrFromINChI *pStruct,
                                inp_ATOM *at,
                                inp_ATOM *at2,
                                VAL_AT *pVA,
                                ALL_TC_GROUPS *pTCGroups,
                                int *pnNumRunBNS,
                                int *pnTotalDelta,
                                int forbidden_edge_mask )
{
    int i, j, neigh, num_endpoints, tg_group = 0, num_success;
    int ret2, ret, delta;
    int num_at = pStruct->num_atoms;
    int num_deleted_H = pStruct->num_deleted_H;
    int len_at = num_at + num_deleted_H;
    int inv_forbidden_edge_mask = ~forbidden_edge_mask;

    /* for RunBnsTestOnce */
    Vertex     vPathStart, vPathEnd;
    int        nPathLen, nDeltaH, nDeltaCharge, nNumVisitedAtoms;

    BNS_EDGE   *pEdgePlus, *pEdgeMinus;
    Vertex      v1p, v2p, v1m, v2m;
    BNS_VERTEX *pv1p, *pv2p, *pv1m, *pv2m;

    /* djb-rwth: removing redundant code */
    num_success = 0;

    /* to simplify, prepare new at[] from pBNS */
    memcpy(at2, at, len_at * sizeof(at2[0]));
    pStruct->at = at2;
    ret2 = CopyBnsToAtom( pStruct, pBNS, pVA, pTCGroups, 1 );
    pStruct->at = at;
    if (ret2 < 0)
    {
        ret = ret2;
        goto exit_function;
    }

    for (i = 0; i < num_at; i++)
    {
        if (pVA[i].cNumValenceElectrons != 4 && /* not C, Si, Ge */
             !pVA[i].cMetal && !pVA[i].nTautGroupEdge &&
             !at2[i].num_H && at2[i].valence >= 3 &&
             at2[i].valence == at2[i].chem_bonds_valence &&
             !at2[i].charge && pVA[i].nCPlusGroupEdge > 0 &&
             is_centerpoint_elem( at2[i].el_number ))
        {
            for (j = 0, num_endpoints = 0; j < at2[i].valence; j++)
            {
                neigh = at2[i].neighbor[j];
                if (at2[neigh].endpoint)
                {
                    if (!num_endpoints)
                    {
                        tg_group = at2[neigh].endpoint;
                    }
                    else if (tg_group != at2[neigh].endpoint)
                    {
                        break; /* not a centerpoint */
                    }
                    num_endpoints++;
                }
            }

            if (j == at2[i].valence && num_endpoints > 1)
            {
                /* found possible centerpoint */
                pEdgePlus = pBNS->edge + ( (long long)pVA[i].nCPlusGroupEdge - 1 ); /* djb-rwth: cast operator added */
                pEdgeMinus = ( pVA[i].nCMinusGroupEdge > 0 ) ? pBNS->edge + ((long long) pVA[i].nCMinusGroupEdge - 1 ) : NULL; /* djb-rwth: cast operator added */
                if (pEdgePlus->flow + ( pEdgeMinus ? pEdgeMinus->flow : 0 ) != 1)
                {
                    continue;
                }
                v1p = pEdgePlus->neighbor1;
                v2p = pEdgePlus->neighbor12 ^ v1p;
                pv1p = pBNS->vert + v1p;
                pv2p = pBNS->vert + v2p;
                if (pEdgeMinus)
                {
                    v1m = pEdgeMinus->neighbor1;
                    v2m = pEdgeMinus->neighbor12 ^ v1m;
                    pv1m = pBNS->vert + v1m;
                    pv2m = pBNS->vert + v2m;
                }
                else
                {
                    v1m = NO_VERTEX;
                    v2m = NO_VERTEX;
                    pv1m = NULL;
                    pv2m = NULL;
                }
                ret = 0;

                /* set new flow to run BNS Search */
                if ((delta = pEdgePlus->flow)) /* djb-rwth: addressing LLVM warning */
                {
                    /* positive charge <=> flow=0 on (=) edge */
                    pEdgePlus->flow -= delta;
                    pv1p->st_edge.flow -= delta;
                    pv2p->st_edge.flow -= delta;
                    pBNS->tot_st_flow -= 2 * delta;
                    pEdgePlus->forbidden |= forbidden_edge_mask;
                    if (pEdgeMinus)
                    {
                        pEdgeMinus->forbidden |= forbidden_edge_mask;
                    }

                    ret = RunBnsTestOnce( pBNS, pBD, pVA, &vPathStart, &vPathEnd, &nPathLen,
                                          &nDeltaH, &nDeltaCharge, &nNumVisitedAtoms );

                    if (ret < 0)
                    {
                        goto exit_function;
                    }

                    if (ret == 1 && ( (vPathEnd == v1p && vPathStart == v2p) ||
                        (vPathEnd == v2p && vPathStart == v1p) ) &&
                                      nDeltaCharge == -1 /* charge moving to this atom disappers*/) /* djb-rwth: addressing LLVM warning */
                    {
                        ret = RunBnsRestoreOnce( pBNS, pBD, pVA, pTCGroups );
                        ( *pnNumRunBNS )++;
                        if (ret < 0)
                        {
                            goto exit_function;
                        }
                        else if (ret == 1)
                        {
                            *pnTotalDelta += ret;
                        }
                        else
                        {
                            ret = RI_ERR_PROGR;
                            goto exit_function;
                        }
                    }
                    else
                    {
                        ret = 0;
                        pEdgePlus->flow += delta;
                        pv1p->st_edge.flow += delta;
                        pv2p->st_edge.flow += delta;
                        pBNS->tot_st_flow += 2 * delta;
                    }
                    pEdgePlus->forbidden &= inv_forbidden_edge_mask;
                    if (pEdgeMinus)
                    {
                        pEdgeMinus->forbidden &= inv_forbidden_edge_mask;
                    }
                }
                else
                {
                    if (pEdgeMinus && ( delta == pEdgeMinus->flow ) && pEdgePlus->flow == 0)
                    {
                        /* positive charge <=> flow=0 on (=) edge and flow=0 on (-) edge */
                        pEdgeMinus->flow -= delta;
                        pv1m->st_edge.flow -= delta;
                        pv2m->st_edge.flow -= delta;
                        pBNS->tot_st_flow -= 2 * delta;
                        pEdgePlus->forbidden |= forbidden_edge_mask;
                        pEdgeMinus->forbidden |= forbidden_edge_mask;
                        ret = RunBnsTestOnce( pBNS, pBD, pVA, &vPathStart, &vPathEnd, &nPathLen,
                                              &nDeltaH, &nDeltaCharge, &nNumVisitedAtoms );
                        if (ret < 0)
                        {
                            goto exit_function;
                        }
                        if (ret == 1 && ( (vPathEnd == v1m && vPathStart == v2m) ||
                                          (vPathEnd == v2m && vPathStart == v1m) ) &&
                                          nDeltaCharge == -1  /* charge moving to this atom disappers*/) /* djb-rwth: addressing LLVM warning */
                        {
                            ret = RunBnsRestoreOnce( pBNS, pBD, pVA, pTCGroups );
                            ( *pnNumRunBNS )++;
                            if (ret < 0)
                            {
                                goto exit_function;
                            }
                            else if (ret == 1)
                            {
                                *pnTotalDelta += ret;
                            }
                            else
                            {
                                ret = RI_ERR_PROGR;
                                goto exit_function;
                            }
                        }
                        else
                        {
                            ret = 0;
                            pEdgeMinus->flow += delta;
                            pv1m->st_edge.flow += delta;
                            pv2m->st_edge.flow += delta;
                            pBNS->tot_st_flow += 2 * delta;
                        }
                        pEdgePlus->forbidden &= inv_forbidden_edge_mask;
                        pEdgeMinus->forbidden &= inv_forbidden_edge_mask;
                    }
                }
                if (ret)
                {
                    num_success++;
                    memcpy(at2, at, len_at * sizeof(at2[0]));
                    pStruct->at = at2;
                    ret2 = CopyBnsToAtom( pStruct, pBNS, pVA, pTCGroups, 1 );
                    pStruct->at = at;
                    if (ret2 < 0)
                    {
                        ret = ret2;
                        goto exit_function;
                    }
                }
            }
        }
    }


    ret = num_success;

exit_function:

    return ret;
}

#endif
