(并查集) poj 2492

#include<iostream>
#include<cstdio>
#include<cstring>
#include<string>
#include<cmath>
#include<cstdlib>
#include<algorithm>
#include<queue>
#include<vector>
#include<stack>
using namespace std;
int n,m;
int fa[1000005],a[1000005];
int find(int x)
{
    if(x!=fa[x])
        fa[x]=find(fa[x]);
    return fa[x];
}
void Union(int x,int y)
{
    int fx,fy;
    fx=find(x),fy=find(y);
    if(fx!=fy)
        fa[fx]=fy;
}
int main()
{
    int tt,x,y,cas=1;
    scanf("%d",&tt);
    while(tt--)
    {
        bool flag=true;
        scanf("%d%d",&n,&m);
        for(int i=1;i<=n;i++)
            fa[i]=i,a[i]=0;
        for(int i=1;i<=m;i++)
        {
            scanf("%d%d",&x,&y);
            int fx,fy;
            fx=find(x),fy=find(y);
            if(fx==fy)
            {
                flag=false;
            }
            if(!a[x])
                a[x]=y;
            else
            {
                Union(a[x],y);
            }
            if(!a[y])
            {
                a[y]=x;
            }
            else
            {
                Union(a[y],x);
            }
        }
        printf("Scenario #%d:\n",cas++);
        if(!flag)
            printf("Suspicious bugs found!\n\n");
        else
            printf("No suspicious bugs found!\n\n");
    }
    return 0;
}