poj 2239 Selecting Courses 最大二分匹配

       把p,q化为一维之后，直接用匈牙利算法

#include<iostream>

using namespace std;



const int MAX = 200;



bool arcs[MAX][MAX];

int match[MAX];

bool isvisit[MAX];

int n, m = 7*12;



int 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 t, p, q;



	while (cin >> n)

	{

		memset(arcs, false, sizeof(arcs));

		memset(match, 0, sizeof(match));



		for (int j = 1; j <= n; j++)

		{

			cin >> t;

			for (int i = 1; i <= t; i++)

			{

				cin >> p >> q;

				arcs[j][12*(p-1) + q] = true;

			}

		}



		int ans = 0;

		for (int i = 1; i <= n; i++)

		{

			memset(isvisit, false, sizeof(isvisit));

			if (find(i))

				ans++;

		}



		cout << ans << endl;

	}

	return 0;

}