匈牙利算法
#include<bits/stdc++.h>
using namespace std;
const int N = 550, M = 1e5 + 10;
int n1, n2, m, h[N], e[M], ne[M], idx;
int match[N], ans;
bool vis[N];
void addEdge(int f, int t)
{
e[idx] = t, ne[idx] = h[f], h[f] = idx ++ ;
}
bool find(int u)
{
for(int i = h[u]; ~i; i = ne[i])
{
int j = e[i];
if(!vis[j])
{
vis[j] = true;
if(!match[j] || find(match[j]))
{
match[j] = u;
return true;
}
}
}
return false;
}
int main()
{
cin >> n1 >> n2 >> m;
memset(h, -1, sizeof h);
for(int i = 0; i < m; i ++ )
{
int f, t;
cin >> f >> t;
addEdge(f, t);
}
for(int i = 1; i <= n1; i ++ )
{
memset(vis, false, sizeof vis);
if(find(i)) ans ++ ;
}
cout << ans << endl;
return 0;
}