过山车

#include <stdio.h>
#include <string.h>
#define inf 0x3ffffff
int mp[501][501],dis[501],vis[501];
int n,m,k;
int find_b(int d)//寻找匹配
{
    for(int i = 1;i <= m;i ++)
    {
        if(!vis[i] && mp[d][i])
        {
            vis[i] = 1;
            if(!dis[i] || find_b(dis[i]))
            {
                dis[i] = d;
                return 1;
            }
        }
    }
    return 0;
}
int main()
{
    while(~scanf("%d",&k)&&k)
    {
        int c = 0,a,b;
        scanf("%d%d",&n,&m);
        memset(mp,0,sizeof(mp));
        memset(dis,0,sizeof(dis));
        for(int i = 0;i < k;i ++)
        {
            scanf("%d%d",&a,&b);
            mp[a][b] = 1;
        }
        for(int i = 1;i <= n;i ++)
        {
            memset(vis,0,sizeof(vis));//每次寻找匹配前都更新，仅仅是防止每次查找时重复访问
            if(find_b(i))c ++;
        }
        printf("%d\n",c);
    }
}