Submission #3907813

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Source Code Expand

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define FOR(I,A,B) for(int I = int(A); I < int(B); ++I)
#define FORR(I,A,B) for(int I = int((B)-1); I >= int(A); --I)
#define REV(x) (reverse(x.begin(),x.end()))

class UnionFind{
public:
	vector<int> par;
	//0-indexed
	void init(int n = 1) {
		par.resize(n);
		for (int i = 0; i < n; ++i) par[i] = i;
	}
	int root(int x = 1){
		if(par[x]==x)return x;
		else{
			return par[x] = root(par[x]);
		}
	}
	void unite(int x = 1,int y = 1){
		x = root(x);
		y = root(y);
		if(x==y)return;
		else par[x] = y;
	}
};

int main(){
	ios::sync_with_stdio(false);
	cin.tie(0);

	int N,M;
	cin >> N >> M;
	vector<int> l[M+1];
	FOR(i,1,N+1){
		int K;
		cin >> K;
		FOR(j,0,K){
			int L;
			cin >> L;
			l[L].push_back(i);
		} 
	}
	UnionFind uf;
	uf.init(N+1);
	FOR(i,1,M+1){
		FOR(j,0,l[i].size()-1){
			uf.unite(l[i][j],l[i][j+1]);
		}
	}

	set<int> se;
	FOR(i,1,N+1){
		se.insert(uf.root(i));
	}
	if(se.size()==1){
		cout << "YES" << endl;
	}else{
		cout << "NO" << endl;
	}
}
// _______  _____  _______  _____  _______ _______ _____ _______ _____ _    _ _______ 
// |       |     | |  |  | |_____] |______    |      |      |      |    \  /  |______ 
// |_____  |_____| |  |  | |       |______    |    __|__    |    __|__   \/   |______ 
//
//  _____   ______  _____   ______  ______ _______ _______ _______ _____ __   _  ______   /
// |_____] |_____/ |     | |  ____ |_____/ |_____| |  |  | |  |  |   |   | \  | |  ____  / 
// |       |    \_ |_____| |_____| |    \_ |     | |  |  | |  |  | __|__ |  \_| |_____| .  
//

Submission Info

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