Array

The O(n) Club: Single Number — How XOR Outsmarts Everyone at the Coding Party ⚡ TL;DR The infamous Single Number problem: there’s one oddball…

The O(n) Club: Largest Rectangle in Histogram – Unleash the Monotonic Stack Mayhem ⚡ TL;DR Want to find the biggest rectangle under a…

The O(n) Club: Sort Colors (LeetCode 75): Dutch Flags, Java, and Pointer-Induced Existential Dread ⚡ TL;DR Need to sort an array of 0s (red),…

The O(n) Club: Next Permutation – Because Arrays Get Bored Too ⚡ TL;DR Given an array, your job is to rearrange it into the next…

The O(n) Club: Sliding Window Maximum — Enjoy O(N) Glory, Deque-Style! ⚡ TL;DR If you’re still brute-forcing the max of every window, please…

The O(n) Club: Permutations: All The Things! (LeetCode 46 & The Backtracking Dance) ⚡ TL;DR Take a bunch of distinct integers and churn…

The O(n) Club: Combination Sum — The Java Dev’s Guide to Backtracking Chaos ⚡ TL;DR Given a set of numbers, find every unique combo (as many…

The O(n) Club: First and Last Index—Where Binary Search Gets Its Groove ⚡ TL;DR Problem: In a sorted array (possibly full of duplicates), find…

The O(n) Club: Jump Game — Greedy or Bust ⚡ TL;DR Here’s the deal: stand at the start of an array, each number = maximum jump forward.…

The O(n) Club: Coin Change, Dynamic Pain Edition ⚡ TL;DR Unlimited coins, fickle denominations, one goal: fewest coins to make your amount.…