Binary Search Tree Iterator

Implement an iterator over a binary search tree (BST). Your iterator is initialized with the root node of a BST.

Calling would return the next smallest number in the next() BST.

Note: next() hasNext() and should run in average O (1) time and uses O (h) memory, where H is the height of the Tree.

Analyse:inorder traversal of BST.

Runtime:28ms.

1 /**2 * Definition for binary tree3 * struct TreeNode {4 * int val;5 * TreeNode *left;6 * TreeNode *right;7 * TreeNode (int x): Val (x), left (null), right (null) {}8  * };9  */Ten classBstiterator { One  Public: ABstiterator (TreeNode *root) { - inorder (root); -     } the  -     /** @return Whether we have a next smallest number*/ -     BOOLHasnext () { -         return!qu.empty (); +     } -  +     /** @return The next smallest number*/ A     intNext () { at         intNextsmallest =Qu.front (); - Qu.pop (); -         returnnextsmallest; -     } - Private: -queue<int>Qu; in      -     voidInorder (treenode*root) { to         if(!root)return; +          -Inorder (root->Left ); theQu.push (root->val); *Inorder (root->Right ); $     }Panax Notoginseng }; -  the /** + * Your Bstiterator 'll be a called like this: A * Bstiterator i = bstiterator (root); the * while (I.hasnext ()) cout << i.next (); +  */

Binary Search Tree Iterator