NSL - Nearest Smallest Element to Left of Every Element

NSR - Nearest Smaller Element to Right of every element

NGR - Nearest Greater Element to Right of every element

NGL - Nearest Greater Element to Left of every element

Score of Parentheses Problem

Verify Preorder Sequence in Binary Search Tree

Find right-most cousin in a binary tree

Number of Steps to Reduce a Number to Zero Problem

Design Circular Queue Problem

Graph Representation - Adjacency List and Map