Perform boundary trversal on a given binary tree.
Delete a node from BST (Binary Search Tree) such that the resultant tree is also a BST.
Given an array of integers, find the length of the longest subarray whose sum is 0.
Given a binary tree, connect the sibling nodes at each level.
Given pre-order & in-order traversal of a binary tree, construct the tree.
Given a sorted array of integers rotated k times, check if given key is present in it?
Given an array of integers and a sum, find a pair that adds up to the sum given.