77. 친구인가?(Disjoint-set : Union&Find 알고리즘)

나의정답.

#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <iostream>
#include <string>
#include <algorithm>
#include <vector>
#include <queue>
#include <stack>

using namespace std;
int unf[1001];
int Find(int v){
	if(v==unf[v]) return v;
	else return unf[v] = Find(unf[v]);
}

void Union(int a, int b){
	a = Find(a);
	b = Find(b);
	if(a != b) unf[a] = b;
}
int main(int argc, char** argv) {
	//freopen("input.txt", "rt", stdin);
	int n, m, a, b;
	scanf("%d %d", &n, &m);
	for(int i = 1; i <= n; i++)
		unf[i] = i;
		
	for(int i = 0; i < m; i++){
		scanf("%d %d", &a, &b);
		Union(a, b);
	}
	
	scanf("%d %d", &a, &b);
	if(Find(a) == Find(b)) printf("YES");
	else printf("NO");
	
}