POJ_2485 Highways

赤裸裸的最小生成树，直接prim算法解决

#include <stdio.h>
#define num 501
#define INF 100000000

int t, n, i, j, k, min, max, tmp, map[num][num], path[num];

void prim()
{
     for (i = 2; i <= n; ++ i)
     {
         path[i] = map[1][i];
     }
     path[1] = -1;
     max = 0;
     for (i = 1; i < n; ++ i)
     {
         min = INF;
         for (j = 1; j <= n; ++ j)
         {
             if (path[j] != -1 && path[j] < min)
             {
                  min = path[j];
                  tmp = j;
             }
         }
         max = min > max ? min : max;
         path[tmp] = -1;
         for (j = 1; j <= n; ++ j)
         {
             if (path[j] > map[tmp][j])
             {
                  path[j] = map[tmp][j];
             }
         }
     }
     printf("%d\n", max);
}

int main()
{
    scanf("%d", &t);
    while (t --)
    {
          scanf("%d", &n);
          for (i = 1; i <= n; ++ i)
          {
              for (j = 1; j <= n; ++ j)
              {
                  scanf("%d", &map[i][j]);
              }
          }
          prim();
    }
    return 0;
}