二分图匹配

Posted 2020-11-04 特特w

匈牙利算法    https://blog.csdn.net/c20180630/article/details/70175814

模板题hdu2063

#include<bits/stdc++.h>
using namespace std;
const int N=550;
int k,m,n,cnt;
bool vis[N];
int ma[N],last[N];
struct orz{
    int v,nex;}e[N*4];
void add(int x,int y)
{
    cnt++;
    e[cnt].v=y;
    e[cnt].nex=last[x];
    last[x]=cnt;
}
bool found(int x)
{
    for (int i=last[x];i;i=e[i].nex)
    {
        if (!vis[e[i].v])
        {
            int v=e[i].v;
            vis[v]=1;
            if (!ma[v]||found(ma[v]))
            {
                ma[v]=x;
                return 1;
            }
        }
    }
    return 0;
}
int main()
{
    while (scanf("%d",&k)&&k)
    {
        scanf("%d%d",&m,&n);
        memset(ma,0,sizeof(ma));
        memset(e,0,sizeof(e));
        memset(last,0,sizeof(last));
        cnt=0;
        int x,y;
        for (int i=1;i<=k;i++)
        {
            scanf("%d%d",&x,&y);
            add(x,y);
        }
        int ans=0;
        for (int i=1;i<=m;i++)
        {
            memset(vis,0,sizeof(vis));
            if (found(i)) ans++;
        }
        printf("%d\n",ans);
    }
}

hdu2063