Codeforces 615A Bulbs

版权声明：本文为博主原创文章，未经博主允许不得转载。 https://blog.csdn.net/polanwind/article/details/87891268

#define _CRT_SECURE_NO_WARNINGS
#include <iostream>
#include <cstdio>
#include <math.h>
#include <string>
#include <algorithm>

using namespace std;

int n, m;
bool vis[105];

int main() {
	scanf("%d %d", &n, &m);
	for (int i = 1;i <= n;++i) {
		int a;
		scanf("%d", &a);
		for (int j = 1;j <= a;++j) {
			int s;
			scanf("%d", &s);
			vis[s] = true;
		}
	}
	bool flag = true;
	for (int i = 1;i <= m;++i) {
		if (vis[i] == false) {
			flag = false;
		}
	}
	if (flag) {
		printf("YES\n");
	}
	else {
		printf("NO\n");
	}
	return 0;
}