HDU1874-畅通工程续-最短路(dijkstra)

#include<iostream>
#include<string>
#include<cstdio>
#include<cstring>
#include<map>
#include<queue>
#include<cmath>
#include<stack>
#include<set>
#include<vector>
#include<algorithm>
#define LL long long
#define inf 1<<29
#define s(a) scanf("%d",&a)
#define CL(a,b) memset(a,b,sizeof(a))
using namespace std;
const int N=205;
int n,m,a,b,c;
int Map

;
int dist
;
bool vis
;
void dijkstra()
{
    CL(vis,false);
    for(int i=1;i<=n;i++) dist[i]=Map[a][i];
    vis[a]=true;
    while(1){
        int v=-1;
        for(int u=1;u<=n;u++){
            if(!vis[u]&&(v==-1||dist[u]<dist[v])) v=u;
        }
        if(v==-1) break;
        vis[v]=true;
        for(int u=1;u<=n;u++){
            dist[u]=min(dist[u],dist[v]+Map[v][u]);
        }
    }
}
int main()
{
    int t;
    while(~scanf("%d%d",&n,&m)){
        n++;
        for(int i=1;i<=n;i++){
            for(int j=1;j<=n;j++)
                Map[i][j]=inf;
            Map[i][i]=0;
        }
        for(int i=0;i<m;i++){
            scanf("%d%d%d",&a,&b,&c);a++;b++;
            if(Map[a][b]>c)
                Map[a][b]=Map[b][a]=c;
        }
        scanf("%d%d",&a,&b);a++;b++;
        dijkstra();
        if(dist[b]==inf) printf("-1\n");
        else printf("%d\n",dist[b]);
    }
    return 0;
}