/*
 * Copyright (c) 2005-2017 National Technology & Engineering Solutions
 * of Sandia, LLC (NTESS).  Under the terms of Contract DE-NA0003525 with
 * NTESS, the U.S. Government retains certain rights in this software.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *
 *     * Redistributions in binary form must reproduce the above
 *       copyright notice, this list of conditions and the following
 *       disclaimer in the documentation and/or other materials provided
 *       with the distribution.
 *
 *     * Neither the name of NTESS nor the names of its
 *       contributors may be used to endorse or promote products derived
 *       from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */

/* Make linked list of elements in each set. */
void make_setlists(int *setlists,  /* space for linked lists of vertices in sets */
                   int *list_ptrs, /* headers of each linked list */
                   int  nsets,     /* number of sets being created this step */
                   int *subsets,   /* subsets being created at current step */
                   int *subassign, /* assignment for vertices in (sub)graph */
                   int *loc2glob,  /* mapping from subgraph to graph numbering */
                   int  subnvtxs,  /* number of vertices in (sub)graph */
                   int  first      /* is this full graph or subgraph? */
)
{
  int set;  /* set a vertex belongs to */
  int i, j; /* loop counters */

  if (first) { /* Don't need to indirect set numbers. */
    for (i = 0; i < nsets; i++) {
      list_ptrs[subsets[i]] = 0;
    }

    for (i = subnvtxs; i; i--) {
      set            = subassign[i];
      setlists[i]    = list_ptrs[set];
      list_ptrs[set] = i;
    }
  }

  else {
    for (i = 0; i < nsets; i++) {
      list_ptrs[subsets[i]] = 0;
    }

    for (i = subnvtxs; i; i--) {
      set            = subsets[subassign[i]];
      j              = loc2glob[i];
      setlists[j]    = list_ptrs[set];
      list_ptrs[set] = j;
    }
  }
}
