Array

The O(n) Club: Remove Element — How to Clean Arrays Without Panic or Pain ⚡ TL;DR LeetCode #27 in plain English: Pretend you actually like…

The O(n) Club: How Many Ways Can You Lose Count? (A Java Dev’s Guide to Combination Sum IV) ⚡ TL;DR You want to count the number of…

The O(n) Club: Number of Longest Increasing Subsequence — Now With Extra Counting! ⚡ TL;DR This isn’t just “find the LIS…

The O(n) Club: Binary Search With Zero Chill (And Full Log n Swagger) ⚡ TL;DR Stop poking every box—binary search slashes sorted arrays in…

The O(n) Club: Search in Rotated Sorted Array II — Why Binary Search Needs Therapy ⚡ TL;DR Rotated sorted array got you feeling dizzy? Now…

The O(n) Club: Constructing BST from Preorder — Recursion, Not Regret ⚡ TL;DR Rebuild a Binary Search Tree from an array that screams…

The O(n) Club: Non-overlapping Intervals — Uninvite Guests, Save the Buffet ⚡ TL;DR Got a stack of intervals and need to make sure none of…

The O(n) Club: Flood Fill (LeetCode 733): When Your Paint Bucket Actually Needs a Manual ⚡ TL;DR You want the code version of MS Paint’s…

The O(n) Club: Maximum Binary Tree—When Your Array Is a Bunch of Control Freaks ⚡ TL;DR Choice: scan for the max, crown it root, recursively…

The O(n) Club: Contains Duplicate—The HashSet Supremacy Edition ⚡ TL;DR Want to bully an array into confessing its duplicates? Toss everything…