Coding Interview Problems

In-depth walkthroughs of coding interview problems from top tech companies

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5 problems
Count paths on a board
Calculate the number of unique paths from top-left to bottom-right in an m×n grid, moving only right or down.
Wildcard Parenthesis Validator
Master the art of validating parentheses with wildcards - a favorite interview problem at Amazon, Microsoft, and Apple that tests your greedy algorithm skills.
Post-Bigram Word Finder
Find all words that appear immediately after a specific two-word sequence in a string - a classic string parsing challenge.
Reverse a linked list
Given the head of a singly linked list, write a method that reverses the list and returns its new head.
Height of a binary tree
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.
Problem Diff.
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