HDOJ1213 How Many Tables

#include<stdio.h>
int father[1001];

int find(int a)
{
	while(father[a]>0)
	{
		a=father[a];
	}
	return a;
}

int main()
{
	int n,m,t,i,a,b,num;
	scanf("%d",&t);
	while(t--)
	{
		num=0;
		scanf("%d%d",&m,&n);
		for(i=1;i<=m;++i)
			father[i]=-1;
		for(i=1;i<=n;++i)
		{
			scanf("%d%d",&a,&b);
			a=find(a);
			b=find(b);
			if(a!=b)
				father[a]=b;
		}
		for(i=1;i<=m;++i)
			if(father[i]<0)
				++num;
		printf("%d\n",num);
	}
	return 0;
}

http://acm.hdu.edu.cn/showproblem.php?pid=1213