courses-二分图最大匹配

#include <iostream>

#include <cstring>

#include <cstdio>

using namespace std;

const int MAXN = 305;

int uN, vN;

bool g[MAXN][MAXN];

int xM[MAXN], yM[MAXN];

bool chk[MAXN];

bool searchPath(int u)

{

	for(int v = 0; v < vN; v++)

		if(g[u][v] && !chk[v])

		{

			chk[v] = true;

			if(yM[v] == -1 || searchPath(yM[v]))

			{

				yM[v] = u;

				xM[u] = v;

				return true;

			}

		}

	return false;

}



int maxMatch()

{

	int u, ret = 0;

	memset(xM, -1, sizeof(xM));

	memset(yM, -1, sizeof(yM));

	for(u = 0; u < uN; u++)

		if(xM[u] == -1)

		{

			memset(chk, false, sizeof(chk));

			if(searchPath(u))ret++;

		}

	return ret;

}

int main()

{

	int icase;

	scanf("%d", &icase);

	while(icase--)

	{

		//矩阵一定要初始化 

		memset(g, 0, sizeof(g));

		int p, n;

		scanf("%d%d", &p, &n);

		uN = p;

		vN = n;

		int cnt, j;

		for(int i = 0; i < p; i++)

		{

			scanf("%d", &cnt);

			while(cnt--)

			{

				scanf("%d", &j);

				//转换为下标从0开始 

				j--;

				g[i][j] = true;

			}

		}

		//每一个课程都只有一个代表 

		if(maxMatch() == p)puts("YES");

		else puts("NO");

	}

	system("pause");

	return 0;

}