USACO 4.2 The Perfect Stall(匈牙利)

二分图最大匹配模版题。

 1 /*
 2  ID: cuizhe
 3  LANG: C++
 4  TASK: stall4
 5 */
 6 #include <cstdio>
 7 #include <cstring>
 8 #include <cmath>
 9 #include <string>
10 #include <ctime>
11 using namespace std;
12 int p[201][201],used[201],linker[201];
13 int n,m;
14 int dfs(int x)
15 {
16     int i;
17     for(i = 1;i <= n;i ++)
18     {
19         if(p[x][i]&&!used[i])
20         {
21             used[i] = 1;
22             if(!linker[i]||dfs(linker[i]))
23             {
24                 linker[i] = x;
25                 return 1;
26             }
27         }
28     }
29     return 0;
30 }
31 int main()
32 {
33     int i,j,num,ev,ans;
34     freopen("stall4.in","r",stdin);
35     freopen("stall4.out","w",stdout);
36     scanf("%d %d",&n,&m);
37     for(i = 1;i <= m;i ++)
38     {
39         scanf("%d",&num);
40         for(j = 1;j <= num;j ++)
41         {
42             scanf("%d",&ev);
43             p[i][ev] = 1;
44         }
45     }
46     ans = 0;
47     for(i = 1;i <= n;i ++)
48     {
49         memset(used,0,sizeof(used));
50         if(dfs(i))
51         ans ++;
52     }
53     printf("%d\n",ans);
54     return 0;
55 }

 

posted @ 2013-03-04 20:39  Naix_x  阅读(149)  评论(0)  编辑  收藏  举报