/*
 * Copyright(C) 1999-2020 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.
 *
 * See packages/seacas/LICENSE for details
 */

#include "structs.h" // for vtx_data
#include <stdio.h>   // for NULL

/* Find the maximum weighted degree of a vertex. */
double find_maxdeg(struct vtx_data **graph,       /* graph data structure */
                   int               nvtxs,       /* number of vertices */
                   int               using_ewgts, /* are edge weights being used? */
                   float *           pmax_ewgt    /* returns largest edge weight if not NULL */
)
{
  double maxdeg;   /* maximum degree of a vertex */
  float *eptr;     /* loops through edge weights */
  float  max_ewgt; /* largest edge weight in graph */
  float  ewgt;     /* edge weight value */
  int    i, j;     /* loop counter */

  /* Find the maximum weighted degree of a vertex. */
  maxdeg = 0;
  if (using_ewgts) {
    if (pmax_ewgt != NULL) {
      max_ewgt = 0;
      for (i = 1; i <= nvtxs; i++) {
        if (-graph[i]->ewgts[0] > maxdeg) {
          maxdeg = -graph[i]->ewgts[0];
        }

        eptr = graph[i]->ewgts;
        for (j = graph[i]->nedges - 1; j; j--) {
          ewgt = *(++eptr);
          if (ewgt > max_ewgt) {
            max_ewgt = ewgt;
          }
        }
      }
      *pmax_ewgt = max_ewgt;
    }
    else {
      for (i = 1; i <= nvtxs; i++) {
        if (-graph[i]->ewgts[0] > maxdeg) {
          maxdeg = -graph[i]->ewgts[0];
        }
      }
    }
  }

  else {
    for (i = 1; i <= nvtxs; i++) {
      if (graph[i]->nedges > maxdeg) {
        maxdeg = graph[i]->nedges - 1;
      }
    }
    if (pmax_ewgt != NULL) {
      *pmax_ewgt = 1;
    }
  }
  return (maxdeg);
}