Submission #995018

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Source Code Expand

#include <bits/stdc++.h>
using namespace std;
typedef long long LL;
vector<int> edges[400000];
int vis[400000];
int ncc = 0;
void dfs(int a){
	if(vis[a]) return;
	vis[a] = 1;
	for(int c = 0; c < edges[a].size(); c++) dfs(edges[a][c]);
}
int main(){
	for(int i = 0; i < 400000; i++) vis[i] = 0;
	int n, m;
	cin >> n >> m;
	for(int i = 0; i < n; i++){
		int z = 0;
		cin >> z;
		for(int j = 0; j < z; j++){
			int x;
			cin >> x;
			edges[i].push_back(x+n-1);
			edges[x+n-1].push_back(i);
		}
	}
	for(int i = 0; i < m+n; i++) vis[i] = 0;
	dfs(0);
	for(int i = 0; i < n; i++){
		if(!vis[i]){
			cout << "NO" << endl;
			return 0;
		}
	}
	cout << "YES" << endl;

}

Submission Info

Judge Result