PKU 1125 【简单floyd】

floyd后遍历下就好

#include <iostream>
#include <cstring>
#include <cstdio>
#include <climits>
const int N = 110;

int map[N][N];
int n;
void floyd()
{
    for(int k=1;k<=n;k++)
     for(int i=1;i<=n;i++)
      for(int j=1;j<=n;j++)
      {
          if(map[i][k]!=-1&&map[k][j]!=-1)
          {
              if(map[i][j]==-1)
              {
                  map[i][j] = map[i][k] + map[k][j];
              }
              else if(map[i][j]>map[i][k]+map[k][j])
              {
                  map[i][j] = map[i][k]+map[k][j];
              }
          }
      }
      /////////////////////////////
      int st=0 ,ans = INT_MAX;
       for(int i=1;i<=n;i++)
       {
           int tans = 0;
           bool flag = false;
         for(int j=1;j<=n;j++)
         {
             if(i!=j)
             {
                 if(map[i][j]==-1)
                 {
                     flag=true;
                     break;
                 }
                 else
                 {
                     if(map[i][j]>tans)
                     {
                         tans = map[i][j];
                     }
                 }
             }

         }
         if(!flag&&ans>tans)
         {
             ans = tans;
             st = i;
         }
       }
       if(st==0)
       {
           printf("disjoint\n");
       }
       else
       {
           printf("%d %d\n",st,ans);
       }

}

using namespace std;

int main()
{
    while(scanf("%d",&n)!=EOF&&n!=0)
    {
        memset(map,255,sizeof(map));
        for(int i=1;i<=n;i++)
        {
            int num;
            scanf("%d",&num);
            for(int j=1;j<=num;j++)
            {
                int v,cost;
                scanf("%d%d",&v,&cost);
                map[i][v] = cost;
            }
        }
        floyd();

    }
    return 0;
}