树结构练习——排序二叉树的中序遍历

http://acm.sdut.edu.cn/sdutoj/problem.php?action=showproblem&problemid=2128

有些忘记了

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 1 #include<stdio.h>

 2 #include<malloc.h>

 3 typedef struct tree

 4 {

 5     struct tree *l,*r;

 6     int data;

 7 }tt;

 8 int k;

 9 void creat(tt *head,int a)

10 {

11     tt *p;

12     p = (tt *)malloc(sizeof(tt));

13     p->data = a;

14     if(head->data>a)//比它小往左走

15     {

16          if(head->l == NULL)

17          {

18              head->l = p;

19              p->l = NULL;

20              p->r = NULL;

21          }

22          else

23              creat(head->l,p->data);

24     }

25     else //否则往右走

26     {

27         if(head->r == NULL)

28          {

29              head->r = p;

30              p->l = NULL;

31              p->r = NULL;

32          }

33          else

34              creat(head->r,p->data);

35     }

36 }

37 void inorder(tt *head)//中序遍历

38 {

39     if(head!=NULL)

40     {        

41         inorder(head->l);

42         if(k!=0)

43             printf(" ");

44         printf("%d",head->data);

45         k++;

46         inorder(head->r);

47     }

48 }

49 int main()

50 {

51     int n,i,j,a;

52     tt *head;

53     head = (tt *)malloc(sizeof(tt));

54     while(scanf("%d",&n)!=EOF)

55     {

56         k = 0;

57         for(i = 1 ;i <= n ; i++)

58         {

59             scanf("%d",&a);

60             if(i == 1)//根节点

61             {

62                 head->data = a;

63                 head->l = NULL;

64                 head->r = NULL;

65             }

66             else

67                 creat(head,a);//插入

68         }

69         inorder(head);

70         printf("\n");

71     }

72     return 0;

73 }