tempcode

 1 #include 
 2 #include 
 3 struct TreeNode 
 4 {
 5     int val;
 6     struct TreeNode *left;
 7     struct TreeNode *right;
 8 };
 9 struct TreeNode * ClimbAsWidth(struct TreeNode *root, int n)
10 {
11     struct TreeNode * temp;
12     if(root->val==n)
13         return root;
14     if(root->left==NULL&&root->right==NULL)
15         return NULL;
16     if(root->left!=NULL)
17         return ClimbAsWidth(root->left, n);
18     if(root->right!=NULL)
19         return ClimbAsWidth(root->right, n);
20     if((temp=ClimbAsWidth(root->left, n))!=NULL)
21         return temp;
22     else if((temp=ClimbAsWidth(root->right, n))!=NULL)
23         return temp;
24     else 
25         return NULL;
26 }
27 
28 struct TreeNode* searchBST(struct TreeNode* root, int val)
29 {
30     return ClimbAsWidth(root, val);
31 }
32 
33 int main()
34 {
35     struct TreeNode root;
36     root.val = 4;
37     root.left = malloc(sizeof(struct TreeNode));
38     root.left->val = 2;
39     root.right = malloc(sizeof(struct TreeNode));
40     root.right->val = 7;
41     root.right->left = NULL;
42     root.right->right = NULL;
43     root.left->left = malloc(sizeof(struct TreeNode));
44     root.left->left->val = 1;
45     root.left->left->left = NULL;
46     root.left->left->right = NULL;
47     root.left->right = malloc(sizeof(struct TreeNode));
48     root.left->left->val = 3;
49     root.left->left->left = NULL;
50     root.left->left->right = NULL;
51     if(searchBST(&root,7)==/*root.right*/NULL)
52         puts("rigth");
53     return 0;
54 }