只需要考虑男生找女生

#include<bits/stdc++.h>
using namespace std;
const int N = 510;
const int M = 1e5+10;
int val[M],ne[M],h[N],idx;
bool st[N];
int n1,n2,m;
int match[N];

void add(int a,int b)
{
    val[idx] = b;
    ne[idx] = h[a];
    h[a] = idx++;
}
bool find(int x)
{
    for(int i = h[x];i != -1;i = ne[i])
    {
        int j = val[i];
        if(!st[j])
        {
            st[j] = true;//已经考虑过了
            if(match[j] == 0 || find(match[j]))//如果可以找到
            {
                match[j] = x;
                return true;
            }
        }
    }
    return false;
}
int main()
{
    cin>>n1>>n2>>m;
    memset(h, -1, sizeof h);
    while (m -- )
    {
        int a,b;
        cin>>a>>b;
        add(a,b);
    }
    int res = 0;
    for(int i = 1;i<=n1;i++)
    {
        memset(st,false,sizeof st);
        if(find(i))res++;
    }
    cout<<res<<endl;
    return 0;
}