hdu1874

[cce_cpp]
#include <iostream>
#include <algorithm>
using namespace std;

#ifndef ONLINE_JUDGE
//最开始想用来练习spfa+邻接表，老是wa,改用floyd + 邻接矩阵，还是wa，最后无奈看了discuss,
//才发现忘记判断起点与终点相同的情况...
#include <fstream>
ifstream fin("test.txt");
#define cin fin
#endif
const int INF = 99999999;
int graph[220][220];
int main()
{
    ios::sync_with_stdio(false);
    int n,m,i,a,b,x,s,t,k,j;
    while(cin >> n >> m)
    {
        for(i = 0; i < n; ++i)
        {
            for(j = 0; j < n; ++j)
            if(i==j)
            graph[i][j]=0;
            else
            graph[i][j] = INF;
        }
        for(i = 0; i < m; ++i)
        {
            cin >> a >> b >> x;
            graph[a][b] = graph[b][a] = x < graph[a][b] ? x : graph[a][b];
        }
        cin >> s >> t;
        for(k = 0; k < n; ++k)
        for(i = 0; i < n; ++i)
        for(j = 0; j < n; ++j)
        if(graph[i][j] > graph[i][k] + graph[k][j])
        graph[i][j] = graph[i][k] + graph[k][j];
        if(graph[s][t]==INF)
        cout << -1 << endl;
        else
        cout << graph[s][t] << endl;
    }
    return 0;
}
[/cce_cpp]