poj 1469 COURSES 最大二分匹配

       这题也是赤裸裸的最大二分匹配。在最后加个判断即可。

       注意，用cin会超时，要用scanf

 

#include<iostream>
using namespace std;

const int MAX = 305;

bool arcs[MAX][MAX];
bool isvisit[MAX];
int match[MAX];
int n, m;

bool find(int u)
{
	for (int i = 1; i <= m; i++)
		if (arcs[u][i] && !isvisit[i])
		{
			isvisit[i] = true;
			if (!match[i] || find(match[i]))
			{
				match[i] = u;
				return true;
			}
		}

		return false;
}

int main()
{
	int k;
	int num;

	int cases;
	cin >> cases;
	while (cases--)
	{
		scanf("%d%d", &n, &m);
		memset(arcs, false, sizeof(arcs));
		memset(match, 0, sizeof(match));
		for (int i = 1; i <= n; i++)
		{
			scanf("%d", &k);
			for (int j = 0; j < k; j++)
			{
				scanf("%d", &num);
				arcs[i][num] = true;
			}
		}

		int ans = 0;
		for (int i = 1; i <= n; i++)
		{
			memset(isvisit, false, sizeof(isvisit));
			if (find(i))
				ans++;
		}

		if (ans == n)
			printf("YES\n");
		else
			printf("NO\n");
		
	}
	return 0;
}