最短路（sp

#include<stdio.h>
#include<iostream>
#include<queue>

using namespace std;

#define N 205
#define INF 99999999

int n,m,map[N][N];
int visited[N],dis[N];

int SPFA(int src,int des){
    int i;
    for(i=0;i<n;i++){
        dis[i]=INF;
        visited[i]=0;
    }
    queue<int> myqueue;
    while(!myqueue.empty())
        myqueue.pop();
    dis[src]=0;
    visited[src]=1;
    myqueue.push(src);
    int tmp;
    while(!myqueue.empty()){
        tmp=myqueue.front();
        myqueue.pop();
        visited[tmp]=0;
        for(i=0;i<n;i++)
            if(dis[i]>dis[tmp]+map[tmp][i]){
                dis[i]=dis[tmp]+map[tmp][i];
                if(!visited[i]){
                    visited[i]=1;
                    myqueue.push(i);
                }
            }
    }
    return dis[des];
}

int main(){
    int u,v,cost;
    while(scanf("%d%d",&n,&m)!=EOF){
        int i,j;
        for(i=0;i<n;i++)
            for(j=0;j<n;j++)
                map[i][j]=INF;
        for(i=0;i<m;i++){
            scanf("%d%d%d",&u,&v,&cost);
            if(cost<map[u][v])
                map[u][v]=map[v][u]=cost;
        }
        int s,t;
        scanf("%d%d",&s,&t);
        int ans=SPFA(s,t);
        if(ans<INF)
            printf("%d
",ans);
        else
            printf("-1
");
    }
    return 0;
}