HDU1213

#include<iostream>
using namespace std;

const int N = 1e4+10;
int p[N];
int t;

int find(int x){
	if(p[x] != x) p[x] = find(p[x]);
	return p[x];
}

int main(){
	cin >> t;
	while(t--){
		int n,m;
		cin >> n >> m;
		for(int i = 1; i <= n; i++) p[i] = i;
		
		while(m--){
			int a,b;
			cin >> a >> b;
			p[find(a)] = find(b);
		}
		int cnt = 0;
		for(int i = 1; i <= n; i++)
			if(p[i] == i) cnt++;
			
		cout << cnt << endl;
	}
	return 0;
	
}

HDU1213

原文：https://www.cnblogs.com/ApStar/p/14643787.html