Submission #4391881

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Source Code Expand

#include <bits/stdc++.h>
using namespace std;

struct unionfind{
	vector<int> data;
	
	unionfind(int n){
		for(int i=0;i<n;i++){
			data.push_back(i);
		}
	}
	
	int find(int x){
		if(data[x]==x)return x;
		return data[x]=find(data[x]);
	}
	
	void unite(int x,int y){
		x=find(x);y=find(y);
		if(x==y)return;
		data[x]=y;
	}
	
	bool check(int x,int y){
		return (find(x)==find(y));
	}
};


int main(){
	int N,M;
	cin>>N>>M;
	unionfind uf(M);
	vector<vector<int>> lang(N);
	
	for(int i=0;i<N;i++){
		int K;
		cin>>K;
		for(int j=0;j<K;j++){
			int x;
			cin>>x;
			x--;
			lang[i].push_back(x);
			if(j!=0)uf.unite(x,lang[i][j-1]);
		}
	}
	
	bool flag = true;
	for(int i=1;i<N;i++){
		if(uf.check(lang[0][0],lang[i][0])==false){
			flag=false;
			break;
		}
	}
	
	if(flag)cout<<"YES"<<endl;
	else cout<<"NO"<<endl;
	
	
	
	
	return 0;
}

Submission Info

Judge Result