poj 3259Wormholes (spfa最短路径)

#include<stdio.h>
#include<string.h>
#include<limits.h>
#include<queue>
using namespace std;
#define N 5505
#define M 55000//注意边和点集的数组大小
struct edge
{
    int to,value,next;
}edges[M];
int heads[N],len=0;
int addedge(int u,int v,int w)
{
    edges[len].to=v,edges[len].value=w,edges[len].next=heads[u];
    heads[u]=len++;
    return 0;
}
int n,m;

int spfa(int v)
{
    queue<int> q;
    int inqueue[N],dis[N];
    memset(inqueue,0,sizeof(inqueue)),inqueue[v]=1;
    q.push(v);
    for(int i=0;i<n;i++) dis[i]=INT_MAX;
    dis[v]=0;
    int times[N];
    memset(times,0,sizeof(times)),times[v]=1;

    while(!q.empty()){
        int x=q.front();
        q.pop();
        inqueue[x]=0;
        for(int j=heads[x];j!=-1;j=edges[j].next){
            int to=edges[j].to,value=edges[j].value;
            if(value+dis[x]<dis[to]){
                dis[to]=value+dis[x];
                if(!inqueue[to]){  //注意已经在队列里面的不用再加入队列
                    if(++times[to]>=n) return 0;
                    inqueue[to]=1,q.push(to);
                }
            }
        }
    }
    return 1;
}
int main(void)
{
    int i,j,t;
    int a,b,c;
    scanf("%d",&t);
    while(t--){
        int w;
        memset(heads,-1,sizeof(heads));//注意不要忘记
        scanf("%d%d%d",&n,&m,&w);
        while(m--){
            scanf("%d%d%d",&a,&b,&c);
            addedge(a-1,b-1,c);
            addedge(b-1,a-1,c);
        
        }
        while(w--){
            scanf("%d%d%d",&a,&b,&c);
            addedge(a-1,b-1,-c);
        }
        if(!spfa(0)) printf("YES
");
        else printf("NO
");
    }
    
}