HDU 2063 过山车（二分图 && 匈牙利 && 最小点覆盖）

 1 #include<cstdio>
 2 #include<iostream>
 3 #include<cstring>
 4 
 5 using namespace std;
 6 
 7 int k, n, m;
 8 int match[505], vis[505], g[505][505];
 9 
10 inline int dfs(int u){
11     for(int i = 1; i <= m; i++){
12         if(g[u][i] && !vis[i]){
13             vis[i] = 1;
14             if(!match[i] || dfs(match[i])){
15                 match[i] = u;
16                 return 1;
17             }
18         }
19     }
20     return 0;
21 }
22 
23 inline int hungary(){
24     memset(match, 0, sizeof(match));
25     int ans = 0;
26     for(int i = 1; i <= n; i++){
27         memset(vis, 0, sizeof(vis));
28         if(dfs(i)) ans++;
29     }
30     return ans;
31 }
32 
33 int main(){
34     while(~scanf("%d%d%d", &k, &n, &m) && k != 0){
35         memset(g, 0, sizeof(g)); 
36         for(int i = 1; i <= k; i++){
37             int a, b;
38             scanf("%d%d", &a, &b);
39             g[a][b] = 1;
40         }
41         printf("%d\n", hungary());
42     }
43     return 0;
44 }