Array

The O(n) Club: Longest Continuous Subarray with Absolute Diff ≤ Limit (or, How to Win at Window-Stretching) ⚡ TL;DR Need the biggest, baddest…

The O(n) Club: Minimum Falling Path Sum — Because Gravity Isn’t Optional ⚡ TL;DR Given a grid of integers, start anywhere up top and fall…

The O(n) Club: Diagonal Traverse — How to Survive the Matrix Zigzag Gauntlet ⚡ TL;DR Zigzag through every element of a 2D matrix by diagonals.…

The O(n) Club: Beautiful Arrangement — Why Backtracking Is Actually Beautiful (Sorry, Not Sorry) ⚡ TL;DR Count permutations of 1 to n where,…

The O(n) Club: Last Stone Weight – Who Knew Smash Bros Was a Heap Problem? ⚡ TL;DR Want to break rocks like a computer-age gladiator? Take the…

The O(n) Club: Longest Arithmetic Subsequence—Now With 99% Less Guessing ⚡ TL;DR Find the longest arithmetic subsequence (LAS) in an array…

The O(n) Club: Last Stone Weight II—Divide, Conquer, (Don’t Smash) ⚡ TL;DR Ignore the chaotic demo derby. This problem is really about…

The O(n) Club: When Buckets and Birds Outsmart Sorting — Maximum Gap Edition ⚡ TL;DR If you want the biggest gap between numbers after…

The O(n) Club: Partition Array for Maximum Sum – Your Brain vs. Brute Force ⚡ TL;DR Split your array into chunks of up to k—not exactly k, not…

The O(n) Club: Wiggle Sort II — The Interview Pattern That Spoils Dev Confidence ⚡ TL;DR If you still think Wiggle Sort II is just another…