二分图

 1 #include<cstdio>
 2 #include<cstring>
 3 int n,m,k,ans;
 4 int a,b,c;
 5 int cp[1010];
 6 bool v[1010];
 7 int h[1010],hs;
 8 struct edge{int s,n;}e[1000010];
 9 bool Hungarian_algorithm(int k){
10     for(int i=h[k];i;i=e[i].n) if(!v[e[i].s]){
11         v[e[i].s]=1;
12         if(!cp[e[i].s]||Hungarian_algorithm(cp[e[i].s])){
13             cp[e[i].s]=k;
14             return true;
15         }
16     }
17     return false;
18 }
19 int main(){
20     scanf("%d%d%d",&n,&m,&k);
21     for(int i=1;i<=k;i++){
22         scanf("%d%d",&a,&b);
23         if(a>0&&a<=n&&b>0&&b<=m)
24         e[++hs]=(edge){b,h[a]},h[a]=hs;
25     }
26     for(int i=1;i<=n;i++){
27         memset(v,0,sizeof(v));
28         if(Hungarian_algorithm(i)) ans++;
29     }
30     printf("%d\n",ans);
31     return 0;
32 }