BZOJ 1715: [Usaco2006 Dec]Wormholes 虫洞

spfa 判断负环
当某一个点被更新次数 ≥n 就表示有负环
直接 spfa 果上就好了

#include
#include
#include
#define g getchar()
#define ll long long
#define inf 0x3f3f3f3f
using namespace std;
inline ll read(){
    ll x=0,f=1;char ch=g;
    for(;ch<'0'||ch>'9';ch=g)if(ch=='-')f=-1;
    for(;ch>='0'&&ch<='9';ch=g)x=x*10+ch-'0';
    return x*f;
}
inline void out(ll x){
    int a[25],wei=0;
    if(x<0)putchar('-'),x=-x;
    for(;x;x/=10)a[++wei]=x%10;
    if(wei==0){puts("0");return;}
    for(int j=wei;j>=1;--j)putchar('0'+a[j]);
    putchar('\n');
}
struct re{int v,w,next;}ed[7005];
int dui[2500*500+5],dis[2505],n,head[2505],F,m,mm,e,inq[2505];
bool pd[2505],fl;
int clear(){
    memset(dis,inf,sizeof(dis));
    memset(inq,0,sizeof(inq));
    memset(pd,0,sizeof(pd));
    memset(head,0,sizeof(head));
    fl=0;e=0;
}
inline int ins(int x,int y,int w){ed[++e]=(re){y,w,head[x]};head[x]=e;}
int spfa(int x){
    int tou=1,wei=1;
    dui[1]=x;
    if(inq[x])return 0;
    memset(inq,0,sizeof(inq));
    memset(dis,inf,sizeof(dis));
    inq[x]=1;dis[x]=0;
    for(;tou<=wei;pd[dui[tou++]]=0){
        int u=dui[tou];
        if(inq[u]>n){fl=1;return 0;}
        for(int i=head[u];i;i=ed[i].next){
            int v=ed[i].v;
            if(dis[v]>dis[u]+ed[i].w){
                dis[v]=dis[u]+ed[i].w;
                ++inq[v];
                if(!pd[v])dui[++wei]=v,pd[v]=1;
            }
        }
    }
    if(dis[x]<0)fl=1;
    return 0;
}
int main(){
//  freopen("","r",stdin);
//  freopen("","w",stdout);
    F=read();
    for(;F--;){
        clear();
        n=read();m=read();mm=read();
        for(int i=1;i<=m;++i){int x=read(),y=read(),w=read();ins(x,y,w);ins(y,x,w);}
        for(int i=1;i<=mm;++i){int x=read(),y=read(),w=read();ins(x,y,-w);}
        for(int i=1;i<=n;++i){if(fl)break;spfa(i);}
        puts(fl?"YES":"NO");
    }
    return 0;
}