hdu2063 过山车（最大二分匹配）

 1 #include "iostream"
 2 #include "vector"
 3 #include "memory.h"
 4 using namespace std;
 5 #define swap(a,b,t) ( (t) = (x),(x) = (y),(y) = (t) )
 6 #define MAXN 1010
 7 int l[MAXN][MAXN];
 8 bool flag[MAXN];
 9 int re[MAXN];
10 int k,m,n;
11 int ans;
12 
13 int find(int a)
14 {
15     for (int i = 0;i <= n; ++ i) {
16         if (l[a][i] == 1 && flag[i] == 0) {
17             flag[i] = 1;
18             if (re[i] == 0 || find(re[i])) {
19                 re[i] = a;
20                 return 1;
21             }
22         }
23     }
24     return 0;
25 }
26 
27 void init()
28 {
29     ans = 0;
30     for (int i = 0;i <= m; ++ i)
31         for (int j = 0;j <= n; ++ j)
32             l[i][j] = 0;
33     memset(re,0,sizeof(re));
34 }
35 
36 int main()
37 {
38 
39     while (cin >> k,k) {
40         init();
41         ans = 0;
42         cin >> m >> n;
43         for (int i = 0; i < k; ++ i) {
44             int a,b;
45             cin >> a >> b;
46             l[a][b] = 1;
47         }
48         for(int i = 1;i <= m; ++ i)    {
49             memset(flag,0,sizeof(flag));
50             if (find(i)) ans ++;
51         }
52         cout << ans << endl;
53     }
54     return 0;
55 }