hdu 3081 二分图最大匹配

利用并查集建好图后：不断地求最大匹配、删除匹配边直到最大匹配不够n。

#include <algorithm>
#include <iostream>
#include <cstring>
#include <cstdio>
using namespace std;

const int N = 101;
bool mp[N][N];
int mark[N];
bool visit[N];
int fa[N];
int n, m, f;

struct Edge 
{
    int from, to;
} edge[N * N];

int findf( int x )
{
    if ( fa[x] != x ) fa[x] = findf(fa[x]);
    return fa[x];
}

void union_set( int x, int y )
{
    x = findf(x), y = findf(y);
    if ( x != y )
    {
        fa[x] = y;
    }
}

int dfs( int u )
{
    for ( int i = 1; i <= n; i++ )
    {
        if ( !visit[i] && mp[u][i] )
        {
            visit[i] = 1;
            if ( mark[i] == -1 || dfs(mark[i]) )
            {
                mark[i] = u;
                return 1;
            }
        }
    }
    return 0;
}

int hunagry()
{
    int res = 0;
    memset( mark, -1, sizeof(mark) );
    for ( int i = 1; i <= n; i++ )
    {
        memset( visit, 0, sizeof(visit) );
        res += dfs(i);
    }
    return res;
}

void deleteEdge()
{
    for ( int i = 1; i <= n; i++ )
    {
        mp[mark[i]][i] = 0;
    }
}

int main ()
{
    int t;
    scanf("%d", &t);
    while ( t-- )
    {
        scanf("%d%d%d", &n, &m, &f);
        for ( int i = 1; i <= m; i++ ) scanf("%d%d", &edge[i].from, &edge[i].to);
        memset( mp, 0, sizeof(mp) );
        for ( int i = 1; i <= n; i++ ) fa[i] = i;
        for ( int i = 1; i <= f; i++ )
        {
            int p, q;
            scanf("%d%d", &p, &q);
            union_set( p, q );
        }
        for ( int i = 1; i <= m; i++ )
        {
            mp[findf(edge[i].from)][edge[i].to] = 1;
        }
        for ( int i = 1; i <= n; i++ )
        {
            int o = findf(i);
            if ( o == i ) continue;
            for ( int j = 1; j <= n; j++ )
            {
                mp[i][j] = mp[o][j];
            }
        }
        int ans = 0;
        while ( hunagry() == n )
        {
            ans++;
            deleteEdge();
        }
        printf("%d
", ans);
    }
    return 0;
}