Submission #3631711

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Source Code Expand

#include<iostream>
#include<string>
#include<algorithm>
#include<vector>
#include<queue>
#include<unordered_map>
#include<stack>
#include<random>
#include<set>
#include<map>
#include<functional>
using namespace std;
#define int long long
#define inf 1145141919
#define rep(i,n) for(int i=0;i<n;i++)
typedef pair<int, int>P;
typedef pair<int, P> PP;
struct edge { int to, cost; };
const long long mod = 10000000;
vector<int>G[200001];
int vst[200001];

int dfs(int now) {
	rep(i, G[now].size()) {
		if (vst[G[now][i]] == 0) {
			vst[G[now][i]] = 1;
			dfs(G[now][i]);
		}
	}
	return 0;
}
signed main() {
	int n, m; cin >> n >> m;
	rep(i, n) {
		int k; cin >> k;
		rep(j, k) {
			int l; cin >> l;
			G[i].push_back(n + l - 1);
			G[n + l - 1].push_back(i);
		}
	}
	dfs(0);
	int sum = 0;
	rep(i, n)sum += vst[i];
	if (sum == n)puts("YES");
	else puts("NO");
}

Submission Info

Judge Result