Hdu_1845 Jimmy’s Assignment -最大匹配裸题

题意：裸题，看清楚边数不多这个条件就可以了。

/************************************************
Author        :DarkTong
Created Time  :2016/8/1 20:29:16
File Name     :Hdu_1845.cpp
*************************************************/

//#include <bits/stdc++.h>
#include <cstdio>
#include <cstring>
#include <vector>
using namespace std;
const int maxn = 5000 + 10;
vector<int> w[maxn];
int n, m;
int Left[maxn];
bool used[maxn];
bool match(int i)
{
    for(int j=0;j<w[i].size();++j) if(!used[w[i][j]])
    {
        int v = w[i][j];
        used[v] = true;
        if(!Left[v]||match(Left[v]))
        {
            Left[v] = i;
            return true;
        }
    }
    return false;
}
//返回最大匹配数
int hungary()
{
    int res=0;
    memset(Left, 0, sizeof(Left));
    for(int i=1;i<=n;++i)
    {
        memset(used, 0, sizeof(used));
        if(match(i)) res++;
    }
    return res;
}

int main()
{
    int T, cas=1;
    scanf("%d", &T);
    while(T--)
    {
        for(int i=0;i<maxn;++i) w[i].clear();
        int k, u, v;
        scanf("%d", &n);
        k = 3*n/2;
        for(int i=1;i<=k;++i)
        {
            scanf("%d%d", &u, &v);
            w[u].push_back(v);
            w[v].push_back(u);
        }
        printf("%d\n", hungary()>>1);
    }

    return 0;
}