Submission #1680595

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Source Code Expand

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

const int MAXN = 1e5+5;

int n, m;
vector<int> lan[MAXN];
vector<int> g[MAXN];
bool vis[MAXN];

int ct = 0;

void dfs(int v) {
	vis[v] = 1;
	ct++;

	for (int u : g[v])
		if (!vis[u])
			dfs(u);
}

int main() {
	cin >> n >> m;
	
	for (int i = 0; i < n; ++i) {
		int k; cin >> k;
		for (int j = 0; j < k; ++j) {
			int t; cin >> t;
			lan[t].push_back(i);
		}
	}

	for (int i = 0; i <= m; ++i) {
		for (int j = 0; j < (int)lan[i].size() - 1; ++j) {
			g[lan[i][j]].push_back(lan[i][j+1]);
			g[lan[i][j+1]].push_back(lan[i][j]);
		}
	}

	dfs(0);
	if (ct == n) {
		cout << "YES\n";
	} else {
		cout << "NO\n";
	}
}

Submission Info

Judge Result