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;

}