二分图匹配模板

//
#include
#include
#include
#define MaxN 510
using namespace std;
int from[MaxN];
vector g[MaxN];
bool used[MaxN];

bool match(int num)
{
	int i;
	for(i = 0; i < g[num].size(); i++)
	{
		if(!used[g[num][i]])
		{
			used[g[num][i]] = true;
			if(from[g[num][i]] == 0 || match(from[g[num][i]]))
			{
				from[g[num][i]] = num;
				return true;
			}
		}
	}
	return false;
}
int hungary(int n)
{
	int i;
	int tot = 0;
	memset(from, 0, sizeof(from));
	for( i = 1; i <=n; i++)
	{
		memset(used, 0, sizeof(used));
		if(match(i))
			tot ++;
	}
	return tot;
}
//如果要a-b加一条边，则 g[a].push_back(b);