二分图匹配【模板】

传送门：

#include <cstdio>
#include <cstring>
#include <cmath>
using namespace std;
#define ll long long
#define re register
const int N=1005;
inline void read(int &a)
{a=0;int d=1;char ch;while(ch=getchar(),ch>'9'||ch<'0')if(ch=='-')d=-1;a=ch^48;while(ch=getchar(),ch>='0'&&ch<='9')a=(a<<3)+(a<<1)+(ch^48);a*=d;
}
bool vis[N][N],book[N];
int mata[N],matb[N],n,m;
inline bool dfs(int u)
{for(re int i=1;i<=m;i++){if(book[i]==0&&vis[u][i]==1){book[i]=1;if(matb[i]==0||dfs(matb[i])){matb[i]=u;mata[u]=i;return 1;}}}return 0;
}
int main()
{int e;read(n);read(m);read(e);for(re int i=1;i<=e;i++){int a,b;read(a);read(b);if(a<1||b<1||a>n||b>m)continue;vis[a][b]=1;//vis[b][a]=1;
    }int ans=0;for(re int i=1;i<=n;i++){memset(book,0,sizeof(book));ans+=dfs(i);}printf("%d",ans);return 0;
}