Construct Binary Search Tree from Preorder Traversal.
Given the preorder traversal of a binary tree. We have to write a code to return the root node of a binary search tree that matches the given preorder traversal.
Binary Tree Level Order Traversal II. Given a binary tree, return the bottom-up level order traversal of its node’s values. (ie, from left to right, level by level from leaf to root).
OR
Given a binary tree, return the reverse level order traversal of its nodes’ values. (i.e, from left to right and from the last level to starting level).