hdu2680 Choose the best route 最短路（多源转单源）

#include<iostream>
#include<cstdio>
#include<cstring>
#include<queue>
#include<algorithm>
using namespace std;
const int N = 1010, M=20010;
const int INF = 0x3f3f3f3f;
struct node
{
    int to, w, next;
};
node edge[M];
int head[N], dist[N], outq[N];
bool vis[N];
int tot;
bool SPFA(int s, int n )
{
    int i,k;
    for(i=0;i<=n;i++) dist[i]=INF;
    memset(vis,0,sizeof(vis));
    memset(outq,0,sizeof(outq));
    queue<int > q;
    while(!q.empty()) q.pop();
    vis[s]=1;
    dist[s]=0;
    q.push(s);
    while(!q.empty())
    {
        int u=q.front();
        q.pop();
        vis[u]=0;
        outq[u]++;
        if(outq[u]>n) return 0 ;
        k=head[u];
        while(k>=0)
        {
            if(dist[edge[k].to]-edge[k].w>dist[u])
            {
                dist[edge[k].to]=dist[u]+edge[k].w;
                if(!vis[edge[k].to])
                {
                    vis[edge[k].to]=1;
                    q.push(edge[k].to);
                }
            }
            k=edge[k].next;
        }
    }
    return 1;
}
void addedge(int i,int j,int w)
{
    edge[tot].to=j;
    edge[tot].w=w;
    edge[tot].next=head[i];
    head[i]=tot++;
}
void init()
{
    tot=0;
    memset(head,-1,sizeof(head));
}
int main()
{
    //freopen("test.txt","r",stdin);
    int i,j,k,n,m,t,s;
    while(scanf("%d%d%d",&n,&m,&t)!=EOF)
    {
        init();
        while(m--)
        {
            scanf("%d%d%d",&i,&j,&k);
            addedge(i,j,k);
        }
        scanf("%d",&k);
        for(i=0;i<k;i++)
        {
            scanf("%d",&s);
            addedge(n+1,s,0);
        }
        SPFA(n+1,n+1);
        if(dist[t]==INF) printf("-1\n");
        else printf("%d\n",dist[t]);
    }
    return 0;
}