Coding Interview Problems

Calculate the number of unique paths from top-left to bottom-right in an m×n grid, moving only right or down.

Master the art of validating parentheses with wildcards - a favorite interview problem at Amazon, Microsoft, and Apple that tests your greedy algorithm skills.

Find all words that appear immediately after a specific two-word sequence in a string - a classic string parsing challenge.

Given the head of a singly linked list, write a method that reverses the list and returns its new head.

Given the root TreeNode of a binary tree, write a method return its height. An empty tree has a height of 0 while a single node tree has a height of 1.