匈牙利算法求二分图求最大匹配

Posted 2020-07-11 icode-xiaohu

　　无向图匈牙利算法求地的值除以2才是答案，因为每个边都匹配了两次，有向图算法得出的就是答案。

#include<iostream>
#include<cstdio>
#include<cstring>
using namespace std;
int maps[50][50],match[50],vis[50],n;
bool Find(int u)
{
    cout<<"the fa = "<<u<<endl;
    for(int i = 1; i <= n; i++)
    {
        if(maps[u][i])
        {
            if(!vis[i])
            {
                vis[i] = 1;
                if(match[i] == -1 || Find(match[i]))
                {
                    cout<<"the son = "<<i<<endl;
                    match[i] = u;
                    return true;
                }
                else cout<<"don‘t find his son"<<endl;
            }
        }
    }
    return false;
}
int slove()
{
    memset(match,-1,sizeof(match));
    int ans = 0;
    for(int i = 1; i <= n; i++)
    {
        memset(vis,0,sizeof(vis));
        if(Find(i))
        ans++;
    }
    return ans;
}
int main()
{
    int m,a,b,t;
    ///freopen("Ain.txt","r",stdin);
    cin>>t;
    while(t--)
    {
        memset(maps,0,sizeof(maps));
        cin>>n>>m;
        while(m--)
        {
            cin>>a>>b;
            maps[b][a] = 1;
            maps[a][b] = 1;
        }
        int ans = slove();
        cout<<"ans = "<<ans/2<<endl;
    }
    return 0;
}