HDU 2063 (匈牙利算法) 过山车

 1 //#define LOCAL
 2 #include <iostream>
 3 #include <cstdio>
 4 #include <cstring>
 5 using namespace std;
 6 
 7 const int maxn = 505;
 8 int line[maxn][maxn], used[maxn], girl[maxn];
 9 int k, m, n;
10 
11 bool find(int x)
12 {
13     for(int j = 1; j <= m; ++j)
14     {
15         if(line[x][j] && !used[j])
16         {
17             used[j] = 1;
18             if(girl[j] == 0 || find(girl[j]))
19             {
20                 girl[j] = x;
21                 return true;
22             }
23         }
24     }
25     return false;
26 }
27 
28 int main(void)
29 {
30     #ifdef LOCAL
31         freopen("2063in.txt", "r", stdin);
32     #endif
33 
34     while(scanf("%d", &k) == 1 && k)
35     {
36         scanf("%d%d", &n, &m);
37         memset(line, 0, sizeof(line));
38         memset(girl, 0, sizeof(girl));
39         for(int i = 0; i < k; ++i)
40         {
41             int a, b;
42             scanf("%d%d", &a, &b);
43             line[a][b] = 1;
44         }
45         int match = 0;
46         for(int i = 1; i <= n; ++i)
47         {
48             memset(used, 0, sizeof(used));
49             if(find(i))    ++match;
50         }
51         printf("%d\n", match);
52     }
53     return 0;
54 }