course（二分匹配）hdoj

一道裸的二分匹配

AC代码：

#include<bits/stdc++.h>
using namespace std;
const int maxn = 305;
int edge[maxn][maxn], vis[maxn], link[maxn];
int n, p;
int find(int x)
{
	for (int i = 1; i <=n; i++)
	{
		if (edge[x][i] == 1 && vis[i] == 0)
		{
			vis[i] = 1;
			if (link[i] == -1 || find(link[i])) {
				link[i] = x;
				return 1;
			}
			
		}
	}
	return 0;
}
int hungary()
{
	memset(link, -1, sizeof(link));
	int ans = 0;
	for (int i = 1; i <=p; i++)
	{
		memset(vis, 0, sizeof(vis));
		if (find(i))ans++;
	}
	return ans;
}
int main()
{
	int t;
	cin >> t;
	while (t--)
	{
		memset(edge, 0, sizeof(edge));
		cin >> p >> n;
		int x,y;
		for (int i = 1; i <= p; i++)
		{
			cin >> x;
			while (x--)
			{
				cin >> y;
				edge[i][y] = 1;
			}
		}
		
		if (hungary() == p)
		{
			cout << "YES" << endl;
		}
		else cout << "NO" << endl;
	}
}