hdu2063 过山车（最大二分匹配）

强烈推荐的匈牙利算法介绍：http://www.renfei.org/blog/bipartite-matching.html

 

 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 }

DFS

 

 

欠一个BFS