poj2492A Bug's Life——带权并查集

#include<iostream>
#include<cstdio>
#include<cstring>
using namespace std;
int p,n,m,fa[2005],d[2005];
bool flag;
int find(int x)
{
	if(fa[x]==x)return x;
	else 
	{
		int root=find(fa[x]);
		d[x]+=d[fa[x]];
		fa[x]=root;
	}
	return fa[x];
}
int main()
{
	scanf("%d",&p);
	for(int g=1;g<=p;g++)
	{
		scanf("%d%d",&n,&m);
		int a,b;
		flag=0;
//		memset(fa,0,sizeof fa);
		for(int i=1;i<=n;i++)fa[i]=i;
		memset(d,0,sizeof d);
		for(int i=1;i<=m;i++)
		{
			scanf("%d%d",&a,&b);
			if(flag)continue;
			int u=find(a),v=find(b);
			if(u==v)
				if((d[a]-d[b])%2==0)flag=1;//同性 
			if(u!=v)
			{
				//du+da=db+1;
				fa[u]=v;
				d[u]=d[b]-d[a]+1;
			}
		}
		if(flag)printf("Scenario #%d:\nSuspicious bugs found!\n\n",g);
		else printf("Scenario #%d:\nNo suspicious bugs found!\n\n",g);
	}
}