hdu1285拓扑排序

 1 #include "iostream"

 2 #include "vector"

 3 #include "memory.h"

 4 #include "cstdio"

 5 using namespace std;

 6 #define swap(a,b,t) ( (t) = (x),(x) = (y),(y) = (t) )

 7 #define MAXN 510

 8 int G[MAXN][MAXN];

 9 int indegree[MAXN];

10 int ans[MAXN],t;

11 int n,m;

12 

13 bool toposort()

14 {

15     for (int i = 0;i <= n; ++ i)

16         for (int j = 0;j <= n; ++ j) {

17             if(G[i][j]) indegree[j]++;

18     }

19     for (int i = 0;i < n; ++ i) {

20         int num = 1;

21         while (indegree[num] != 0)

22             num ++;

23         ans[i] = num;

24         indegree[num] = -1;

25         for (int j = 0;j <= n; ++ j) {

26             if (G[num][j] == 1) indegree[j]--;

27         }

28     }

29     return true;

30 }

31 

32 

33 int main()

34 {

35     while (cin >> n >> m) {

36         memset(indegree,0,sizeof(indegree));

37         memset(G,0,sizeof(G));

38         memset(ans,0,sizeof(ans));

39         for (int i = 0;i < m; ++ i) {

40             int a,b;

41             cin >> a >> b;

42             G[a][b] = 1;

43         }

44         if (toposort()) {

45             for (int i = 0;i < n; ++ i) {

46                 cout << ans[i];

47                 if (i != n-1) cout << " ";

48                 else cout << endl;

49             }

50         }

51     }

52     return 0;

53 }

DFS

 1 #include "iostream"

 2 #include "vector"

 3 #include "memory.h"

 4 #include "cstdio"

 5 using namespace std;

 6 #define swap(a,b,t) ( (t) = (x),(x) = (y),(y) = (t) )

 7 #define MAXN 510

 8 int G[MAXN][MAXN];

 9 int indegree[MAXN];

10 int ans[MAXN],t;

11 int n,m;

12 

13 bool toposort()

14 {

15     for (int i = 0;i <= n; ++ i)

16         for (int j = 0;j <= n; ++ j) {

17             if(G[i][j]) indegree[j]++;

18     }

19     for (int i = 0;i < n; ++ i) {

20         int num = 1;

21         while (indegree[num] != 0)

22             num ++;

23         ans[i] = num;

24         indegree[num] = -1;

25         for (int j = 0;j <= n; ++ j) {

26             if (G[num][j] == 1) indegree[j]--;

27         }

28     }

29     return true;

30 }

31 

32 

33 int main()

34 {

35     while (cin >> n >> m) {

36         memset(indegree,0,sizeof(indegree));

37         memset(G,0,sizeof(G));

38         memset(ans,0,sizeof(ans));

39         for (int i = 0;i < m; ++ i) {

40             int a,b;

41             cin >> a >> b;

42             G[a][b] = 1;

43         }

44         if (toposort()) {

45             for (int i = 0;i < n; ++ i) {

46                 cout << ans[i];

47                 if (i != n-1) cout << " ";

48                 else cout << endl;

49             }

50         }

51     }

52     return 0;

53 }

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