1 #include<stdio.h>
2 #include<string.h>
3 #include<algorithm>
4
5 typedef struct TreeNode
6 {
7 int value;
8 struct TreeNode*left;
9 struct TreeNode*right;
10 }*Node;
11 void insert(Node &root,int v)
12 {
13 if(!root)
14 {
15 root=(Node)malloc(sizeof(TreeNode));
16 root->value=v;
17 root->left=NULL;
18 root->right=NULL;
19 }
20 else if(root->value>v)
21 {
22 insert(root->left,v);
23 }
24 else
25 insert(root->right,v);
26 }
27
28 void pre_visit(Node &root)
29 {
30 if(root==NULL)
31 return ;
32 printf("%d ",root->value);
33 pre_visit(root->left);
34 pre_visit(root->right);
35 }
36 void mid_visit(Node &root)
37 {
38 if(root==NULL)
39 return ;
40 mid_visit(root->left);
41 printf("%d ",root->value);
42 mid_visit(root->right);
43 }
44 void last_visit(Node &root)
45 {
46 if(root==NULL)
47 return ;
48 last_visit(root->left);
49 last_visit(root->right);
50 printf("%d ",root->value);
51 }
52 void destroy(Node &root)
53 {
54 if(root==NULL)
55 return;
56 destroy(root->left);
57 destroy(root->right);
58 }
59 int main()
60 {
61 int occure[100000];
62 int n;
63 while(scanf("%d",&n)!=EOF)
64 {
65 Node root=NULL;
66 memset(occure,0,sizeof(occure));
67 int i,temp;
68 for(i=0;i<n;++i)
69 {
70 scanf("%d",&temp);
71 if(!occure[temp])
72 {
73 occure[temp]=1;
74 insert(root,temp);
75 }
76 }
77 pre_visit(root);
78 printf("\n");
79 mid_visit(root);
80 printf("\n");
81 last_visit(root);
82 printf("\n");
83
84 }
85 return 0;
86 }
