匈牙利算法

Posted 2020-10-01 白驹过隙----青春绿

匈牙利算法，用于二分图最大匹配，时间复杂度为O(NM)

话不多说，直接上代码

#include<iostream>
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<algorithm>
#include<cmath>
using namespace std;
int n,m,ans,e[101][101],book[101],match[101];

bool dfs(int u)
{
    int i;
    for(i=1;i<=n;i++)
    {
        if(e[u][i]==1 && book[i]==0)
        {
            book[i]=1;
            if(match[i]==0 || dfs(match[i]))
            {
                match[i]=u;
                match[u]=i;
                return true;
            }
        }
    }
    return false;
}

int main()
{
    int x,y,i;
    scanf("%d%d",&n,&m);
    for(i=1;i<=m;i++)
    {
        scanf("%d%d",&x,&y);
        e[x][y]=1;
        e[y][x]=1;
    }
    memset(match,0,sizeof(match));
    for(i=1;i<=n;i++)
    {
        memset(book,0,sizeof(book));
        if(dfs(i)) ans++;
    }
    printf("%d",ans);
    return 0;
}