自用二分图匹配模板

关于二分图匹配的讲解请看我之前的那篇博客。

 1 #include <iostream>
 2 #include <cstdio>
 3 #include <cstring>
 4 #define maxn 1005
 5 using namespace std;
 6 struct Edge{
 7     int from,to;
 8 };
 9 inline int read(){
10     int num = 0;
11     char c;
12     bool flag = false;
13     while ((c = getchar()) == ' ' || c == '\n' || c == '\r');
14     if (c == '-')
15         flag = true;
16     else
17         num = c - '0';
18     while (isdigit(c = getchar()))
19         num = num * 10 + c - '0';
20     return (flag ? -1 : 1) * num;
21 }
22 Edge edge[maxn*maxn];
23 int head[maxn*2];
24 int tot = 0;
25 void add_edge(int from,int to){
26     edge[++tot].from = head[from];
27     edge[tot].to = to;
28     head[from] = tot;
29 }
30 int n,m,e;
31 bool vis[maxn];
32 int match[maxn];
33 bool dfs_xyl(int x){
34     for (int i=head[x];i;i=edge[i].from){
35         int v = edge[i].to;
36         if (!vis[v]){
37             vis[v] = true;
38             if (!match[v]||dfs_xyl(match[v])){
39                 match[v] = x;
40                 return true;
41             }
42         }
43     }
44     return false;
45 }
46 int main(){
47     n = read();m = read();e = read();
48     for (int i=1;i<=e;i++){
49         int u,v;
50         u = read();v = read();
51         if (u > n || v > m)
52             continue;
53         add_edge(u,v);
54         
55     }
56     int ans = 0;
57     for (int i=1;i<=n;++i){
58         memset(vis,false,sizeof(vis));
59         if(dfs_xyl(i))
60             ans++;
61     }
62     cout << ans << endl;
63     return 0;
64 }

 

posted @ 2017-11-05 23:33  ShawnZhou_Aether  阅读(356)  评论(0)  编辑  收藏  举报