Binary Search Tree Iterator 173

 1 /**
 2  * Definition for binary tree
 3  * struct TreeNode {
 4  *     int val;
 5  *     TreeNode *left;
 6  *     TreeNode *right;
 7  *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 8  * };
 9  */
10 class BSTIterator {
11 public:
12     BSTIterator(TreeNode *root) {
13         
14     }
15 
16     /** @return whether we have a next smallest number */
17     bool hasNext() {
18         
19     }
20 
21     /** @return the next smallest number */
22     int next() {
23         
24     }
25 };
26 
27 /**
28  * Your BSTIterator will be called like this:
29  * BSTIterator i = BSTIterator(root);
30  * while (i.hasNext()) cout << i.next();
31  */