(Dijkstra 输出路径) HDU 1784 畅通工程续

#include<iostream>
#include<algorithm>
#include<cstdio>
#include<stack>
using namespace std;
const int maxn = 210;
const int INF = 0x3f3f3f3f;
int mp[maxn][maxn],vis[maxn],pre[maxn],dis[maxn],n,m,s,t;
void dijkstra(int s){
    for(int i = 0; i < n; i++){
        dis[i] = mp[s][i];
        vis[i] = 0;
        pre[i] = -1;
    }
    vis[s] = 1;
    dis[s] = 0;
    for(int i = 0; i < n; i++){
        int minn = INF,u = 0;
        for(int j = 0; j < n; j++){
            if(vis[j] == 0 && dis[j] < minn){
                minn = dis[j];
                u = j;
            }
        }
        vis[u] = 1;
        for(int j = 0; j < n; j++){
            if(vis[j] == 0 && dis[u] + mp[u][j] < dis[j]){
                dis[j] = dis[u] + mp[u][j];
                pre[j] = u;
            }
        }
    }
} 
int main(){
    while(cin>>n>>m){
        stack<int> St;
        for(int i = 0; i < n; i++){
            for(int j = 0;j < n; j++){
                mp[i][j] = INF;
            }
        }
        int u,v,w;
        for(int i = 0; i < m; i++){
            cin>>u>>v>>w;
            if(w < mp[u][v])
                mp[u][v] = mp[v][u] = w;
        }
        cin>>s>>t;
        dijkstra(s);
        if(dis[t] == INF){
            cout<<-1<<endl;
        }
        else{
            cout<<dis[t]<<endl;
            printf("输出路径：\n");
            int p = t;
            while(pre[p] != -1){
                St.push(p);
                p = pre[p];
            }
            St.push(p);
            cout<<s<<" ";     
            while(!St.empty()){
                int a = St.top();
                cout<<a<<" ";
                St.pop();
            }
        }    
        cout<<endl;
    }
    return 0;
}