Algorithms

Coding-challenge walkthroughs and data-structure problems.

8 articles

• JavaScript Algorithm Interview Problems: 8 Patterns with Solutions

  Learn eight JavaScript algorithm interview patterns with worked solutions: array transforms, hashing, interval scans, matrix rotation, and async sequencing.

  July 21, 2026

• Rotate Image

  You are given an n x n 2D matrix representing an image. Rotate the image by 90 degrees (clockwise).

  September 26, 2022

• Given a set of distinct integers array, return all possible subsets.

  Given a set of distinct integers array ```myArray```, return all possible subsets (the power set).

  September 25, 2022

• Missing Number In An Array

  Given an array containing n distinct numbers taken from 0, 1, 2, ..., n, find the one that is missing from the array.

  September 24, 2022

• How to Square numbers in Array

  should return square array.

  September 15, 2022

• Truth Check using Javascript

  Check if the predicate (second argument) is truthy on all elements of a collection (first argument).

  September 14, 2022

• Merge Intervals using Javascript

  Given a collection of intervals, merge all overlapping intervals.

  June 14, 2021

• Group Anagrams in JavaScript: Two Approaches (Sorted Key vs O(n·k) Count Key)

  Group anagrams in JavaScript two ways: a sorted-string hash key (O(n·k log k)) and the optimal character-count key (O(n·k)). Clean code, complexity analysis, and the interview follow-ups.

  May 22, 2021

Other topics