杭电hdu 1213 How Many Tables并查集

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

并查集基础题，不做任何判断，最后只要统计有几个集合即可。

#include <stdio.h>

#define MAX 1001

int father[MAX];

int n, m;

void init()//初始化
{
	int i;
	for(i = 0; i <= n; i ++){
		father[i] = i;
	}
}

int getfather(int x)//查找父节点
{
	while(x!=father[x])
		x=father[x];
	return x;
}

void join(int a, int b)//将新节点插入到并查集中
{
	int fa = getfather(a);
	int fb = getfather(b);
	if(fa!=fb){
		father[fb] = fa;
	}
}

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