# Problem Definition

## Description

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

Calling `next()` will return the next smallest number in the BST.

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

## Notes

1. [LeetCode discussion - Ideal Solution using Stack (Java)](https://leetcode.com/problems/binary-search-tree-iterator/discuss/52526/Ideal-Solution-using-Stack-(Java))