Courses HDU

#include<iostream>
#include<cstdio>
#include<cstring>
using namespace std;
const int MAXN = 2e5;
int match[MAXN], st[MAXN];
int n,m,p;
int e[MAXN],ne[MAXN],idx,h[MAXN];
void add(int a,int b)
{
	e[idx]=b;
	ne[idx]=h[a];
	h[a]=idx++; 
}
bool find(int x)
{
    for (int i = h[x];i!=-1;i=ne[i])
    {
        int j = e[i];
        if (st[j])
            continue;
        st[j] = 1;
        if (match[j] == -1 || find(match[j]))
        {
            match[j] = x;
            return true;
        }
    }
    return false;
}

int Solve()
{
    int cnt = 0;
    memset(match, -1, sizeof(match));
    for (int i = 1;i <= p;i++)
    {
        memset(st, 0, sizeof(st));
        if (find(i))
            cnt++;
    }
    return cnt;
}

int main()
{
    int t;
    cin >> t;
    while (t--)
    {
    	idx=0;
    	memset(h,-1,sizeof h);
        cin >> p >> n;
        if (p > n)
        {
            cout << "NO" << endl;
            continue;
        }
        for (int i = 1;i <= p;i++)
        {
            int num, v;
            cin >> num;
            while (num--)
            {
                cin >> v;
                add(i,v);
            }
        }
        int cnt = Solve();
        if (cnt < p)
            cout << "NO" << endl;
        else
            cout << "YES" << endl;
    }

    return 0;
}