保留最大边，并且更新用乘号

#include<bits/stdc++.h>
using namespace std;

const int N = 2010,M = 1e5+10;
bool st[N];
double dist[N];
double g[N][N];
int n,m,s,t;

void dijkstra()
{
    //memset(dist,0x3f,sizeof dist);
    dist[s] = 1;
    for(int i = 1;i<=n;i++)
    {
        int t = -1;
        for(int j = 1;j<=n;j++)
            if(!st[j] && (t == -1 || dist[j] > dist[t]))
                t = j;

        st[t] = true;
        for(int j = 1;j<=n;j++) 
            dist[j] = max(dist[j],dist[t] * g[t][j]);
    }
}
int main()
{
    cin>>n>>m;
    while(m--)
    {
        int x,y,z;
        cin>>x>>y>>z;
        double temp = (100.0-z) / 100;
        g[x][y] = g[y][x] = max(g[x][y],temp);
    }
    cin>>s>>t;

    dijkstra();
    printf("%.8lf",100/dist[t]);
    return 0;
}