二分图最大匹配模板 

 1 //洛谷3386 
 2 #include<bits/stdc++.h>
 3 #define N 1005
 4 using namespace std; 
 5 int n,m,s,tot,ans;
 6 int head[N],match[N];
 7 bool vis[N];
 8 inline int read(){
 9     int x=0,f=1; char ch=getchar();
10     while (ch>'9'||ch<'0'){ if (ch=='-') f=-1; ch=getchar(); }
11     while (ch<='9'&&ch>='0'){ x=(x<<3)+(x<<1)+ch-'0'; ch=getchar(); }
12     return x*f;
13 }
14 struct node{
15     int next,to;
16 }e[N*N];
17 void add(int x,int y){
18     e[++tot].next=head[x];
19     head[x]=tot;
20     e[tot].to=y;
21 }
22 bool dfs(int u){
23     for (int i=head[u];i;i=e[i].next){
24         int v=e[i].to;
25         if (vis[v]) continue;
26         vis[v]=true;
27         if (!match[v]||dfs(match[v])){
28             match[v]=u;
29             return true;
30         }
31     }
32     return false;
33 } 
34 int main(){
35     n=read(); m=read(); s=read(); 
36     int x,y;
37     for (int i=1;i<=s;i++){
38         scanf("%d%d",&x,&y);
39         if (x>n||y>m) continue;
40         add(x,y);
41     }
42     for (int i=1;i<=n;i++){
43         memset(vis,0,sizeof(vis));
44         if (dfs(i)) ans++;
45     }
46     printf("%d\n",ans);
47     return 0;
48 }

 

posted @ 2017-09-28 17:57  I__am  阅读(230)  评论(0)    收藏  举报