The O(n) Club: Counting Squares in Binary Matrices (Because Rectangles Are for Quitters)
The O(n) Club: Counting Squares in Binary Matrices (Because Rectangles Are for Quitters) ⚡ TL;DR Counting all squares (not just the “big…
The O(n) Club: Subarray Minimums & The Stack That Outsmarts Brute Force
The O(n) Club: Subarray Minimums & The Stack That Outsmarts Brute Force ⚡ TL;DR Want to sum up the minimum of every contiguous subarray?…
The O(n) Club: Delete and Earn – When House Robber Goes Full Arcade
The O(n) Club: Delete and Earn – When House Robber Goes Full Arcade ⚡ TL;DR Every time you delete a number, you also assassinate its…
The O(n) Club: Detecting 132 Patterns Faster Than Your Interviewer Can Blink
The O(n) Club: Detecting 132 Patterns Faster Than Your Interviewer Can Blink ⚡ TL;DR Find three numbers in an array that say, “Look, I zigged…
The O(n) Club: Pacific Atlantic Water Flow’s Reverse-DFS Party Trick
The O(n) Club: Pacific Atlantic Water Flow’s Reverse-DFS Party Trick ⚡ TL;DR Which cells in a height matrix can get their water to both…
The O(n) Club: Largest Divisible Subset: DP, Java, and Chaos Prevention
The O(n) Club: Largest Divisible Subset—DP, Java, and Chaos Prevention ⚡ TL;DR This problem is basically “who can divide whom at the nerd…
The O(n) Club: Asteroid Collision: Simulate, Stack, Survive (LeetCode 735)
The O(n) Club: Asteroid Collision—Simulate, Stack, Survive (LeetCode 735) ⚡ TL;DR Bunch of asteroids, each moving left or right. When they…
The O(n) Club: Distinct Subsequences, or How to Skip Letters Like a Pro (and Keep Your Sanity)
The O(n) Club: Distinct Subsequences, or How to Skip Letters Like a Pro (and Keep Your Sanity) ⚡ TL;DR Want the number of ways to get t as a…
The O(n) Club: How Many Ways Can You Lose Count? (A Java Dev’s Guide to Combination Sum IV)
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: Remove Element — How to Clean Arrays Without Panic or Pain
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…