P1551 亲戚

并查集还是不熟，还得练

#include<iostream>
#include<set>
#include<map>
#include<algorithm>
#include<vector>
#define int long long
const int N = 1e6;
using namespace std;
char* p1, * p2, buf[100000];
#define nc() (p1==p2 && (p2=(p1=buf)+fread(buf,1,100000,stdin),p1==p2)?EOF:*p1++)
int read()
{
	int x = 0, f = 1;
	char ch = nc();
	while (ch < 48 || ch>57)
	{
		if (ch == '-')
			f = -1;
		ch = nc();
	}
	while (ch >= 48 && ch <= 57)
		x = x * 10 + ch - 48, ch = nc();
	return x * f;
}
int a[N];
int ans = 0;
int n, c;
int f[N];
int find(int x) {//查询并修改父节点
	if (f[x] == x)return x;
	 f[x] = find(f[x]);
	return f[x];
}
void unionn(int x, int y) {
	f[y] = x;
}
signed main() {
	ios::sync_with_stdio(false);
	cin.tie(0);
	cout.tie(0);
	int n, m, p;
	cin >> n >> m>>p;
	for (int i = 1; i <= n; i++)f[i] = i;
	for (int i = 1; i <= m; i++) {
		int p1, p2;
		cin >> p1 >> p2;
		int r1 = find(p1);
		int r2 = find(p2);
		if (r1 != r2)unionn(r1, r2);//合并两个点
	}
	
	for (int i = 1; i <= p; i++) {
		int p1, p2;
		cin >> p1 >> p2;
		if (find(p1) == find(p2))cout << "Yes" << endl;
		else cout << "No" << endl;
	}
	return 0;
}