Q230 Kth Smallest Element in a BST
Q230 Kth Smallest Element in a BST

Given a binary search tree, write a function kthSmallest to find the kth
smallest element in it.

Note:
You may assume k is always valid, 1 ≤ k ≤ BST's total elements.

Follow up:
What if the BST is modified (insert/delete operations) often and you
need to find the kth smallest frequently? How would you optimize the
kthSmallest routine?

robertzm/algotest