hdu 1874 畅通工程续

Floyd 算法

#include <cstdio>
#include <cstring>
#include <algorithm>
#define INF 100000001
using namespace std;
int d[210][210];
int main()
{
    int n,m;
    while(scanf("%d%d",&n,&m) == 2)
    {
        for(int i = 0; i <= n; i++)
            for(int j = 0; j <= n; j++)
            {
                if(i == j)
                    d[i][j] = 0;
                else
                    d[i][j] = INF;
            }
        for(int i = 0; i < m; i++)
        {
            int u, v, w;
            scanf("%d%d%d",&u,&v,&w);
            if(w < d[u][v])
                d[u][v] = d[v][u] = w;
        }
        for(int k = 0; k < n; k++)
            for(int i = 0; i < n; i++)
                for(int j = 0; j < n; j++)
                {
                    d[i][j] = min(d[i][j], d[i][k]+d[k][j]);
                }
        int x,y;
        scanf("%d%d",&x,&y);
        if(d[x][y] < INF)
            printf("%d\n",d[x][y]);
        else
            puts("-1");
    }
    return 0;
}