luogu3386【模板】二分图最大匹配

二分图最大匹配板子

#include <bits/stdc++.h>using namespace std;#define ll long long#define inf 0x3f3f3f3f#define N 1010inline int read(){    int x=0,f=1;char ch=getchar();    while(ch<'0'||ch>'9'){if(ch=='-')f=-1;ch=getchar();}    while(ch>='0'&&ch<='9') x=x*10+ch-'0',ch=getchar();    return x*f;}int n,m,num,ans=0,boy[N],h[N];struct edge{    int to,next;}data[N*N];bool f[N];bool find(int x){    for(int i=h[x];i;i=data[i].next){        int y=data[i].to;if(f[y]) continue;f[y]=1;        if(!boy[y]||find(boy[y])){            boy[y]=x;return 1;        }    }return 0;}int main(){//  freopen("a.in","r",stdin);    n=read();m=read();num=read();    for(int i=1;i<=num;++i){        int x=read(),y=read();if(y>m) continue;        data[i].to=y;data[i].next=h[x];h[x]=i;    }    for(int i=1;i<=n;++i){        memset(f,0,sizeof(f));if(find(i)) ans++;    }    printf("%d\n",ans);    return 0;}