AC的代码

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

int n,m;
int dis[110][110];

int main(){
    cin >> n >> m;
    memset(dis,0x3f,sizeof dis);
    int x,y,z;
    for(int i = 1;i <= n;i++){
        dis[i][i] = 0;
    }
    for(int i = 1;i <= m;i++){
        cin >> x >> y >> z;
        dis[x][y] = dis[y][x] = min(z,dis[x][y]);
    }
    for(int k = 1;k <= n;k++){
        for(int i = 1;i <= n;i++){
            for(int j = 1;j <= n;j++){
               if(dis[i][j] > dis[i][k] + dis[k][j]){
                   dis[i][j] = dis[i][k] + dis[k][j];
               }
            }
        }
    }
    cout << dis[1][n];
    return 0;
}