Poj 1469 COURSES -二分图最大匹配裸题

题目：问course是否有完美匹配

/************************************************
Author        :DarkTong
Created Time  :2016/7/30 22:28:35
File Name     :Poj_1469.cpp
*************************************************/

#include <cstdio>
#include <cstring>
#include <iostream>
#include <algorithm>
#include <vector>
#include <queue>
#include <set>
#include <map>
#include <string>
#include <cmath>
#include <cstdlib>
#include <ctime>

#define INF 0x3f3f3f3f
#define esp 1e-9
typedef long long LL;
//using namespace std;
#define min(a, b) a<b?a:b
#define max(a, b) a>b?a:b
const int maxn = 300 + 10;
int W[maxn*3][maxn], n, m;
int left[maxn];
bool used[maxn];
bool match(int i)
{
    for(int j=1;j<=n;++j) if(W[j][i]&&!used[j])
    {
        used[j] = true;
        if(!left[j]||match(left[j]))
        {
            left[j] = i;
            return true;
        }
    }
    return false;
}
int hungary()
{
    int res=0;
    memset(left, 0, sizeof(left));
    for(int i=1;i<=m;++i)
    {
        memset(used, 0, sizeof(used));
        if(match(i)) res++;
    }
    return res;
}
int main()
{
    int T;
    scanf("%d", &T);
    while(T--)
    {
        memset(W, 0, sizeof(W));

        scanf("%d%d", &m, &n);
        for(int i=1;i<=m;++i)
        {
            int t, x;
            scanf("%d", &t);
            for(int j=0;j<t;++j)
            {
                scanf("%d", &x);
                W[x][i]=1;
            }
        }
        if(hungary()==m) puts("YES");
        else puts("NO");

    }
    return 0;
}