Submission #992408

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Source Code Expand

#include <iostream>
#include <vector>

using namespace std;

int parent[100000];

void init(int n) {
	while (n--)
		parent[n] = n;
}

int find(int x) {
	return parent[x] != x ? parent[x] = find(parent[x]) : x;
}

inline void unite(int x, int y) {
	parent[find(y)] = find(x);
}

vector<int> l[100000];

int main() {
	int n, m;

	cin >> n >> m;
	for (int i = 0; i < n; i++) {
		int k;
		cin >> k;
		for (int j = 0; j < k; j++) {
			int li;
			cin >> li;
			l[li - 1].emplace_back(i);
		}
	}

	init(n);
	for (int i = 0; i < m; i++)
		for (int j = 1; j < l[i].size(); j++)
			unite(l[i][0], l[i][j]);

	const int hoge = find(0);
	for (int i = 1; i < n; i++)
		if (find(i) != hoge) {
			cout << "NO" << endl;
			return 0;
		}

	cout << "YES" << endl;

	return 0;
}

Submission Info

Judge Result