The O(n) Club: Running Sum of 1D Array – Because If You Can’t Count, You Can’t Code
The O(n) Club: Running Sum of 1D Array – Because If You Can’t Count, You Can’t Code ⚡ TL;DR Add up each number as you go; every…
The O(n) Club: Max Consecutive Ones: Give Your CPU a Break, Not a Headache
The O(n) Club: Max Consecutive Ones — Give Your CPU a Break, Not a Headache ⚡ TL;DR Want the longest streak of 1s in a binary array? Count as…
The O(n) Club: Cherry Pickup — How to Outwit a Grid of Thorns, Robots, and Regret
The O(n) Club: Cherry Pickup — How to Outwit a Grid of Thorns, Robots, and Regret ⚡ TL;DR Pick cherries in a grid, dodge the thorns, go from…
The O(n) Club: Design HashMap—Trust Issues, Buckets, and Chaos
The O(n) Club: Design HashMap—Trust Issues, Buckets, and Chaos ⚡ TL;DR Building your own HashMap in Java: for when Copy-Paste isn’t…
The O(n) Club: Valid Triangle Number: Why Sticks Need Therapy (And Sorting)
The O(n) Club: Valid Triangle Number — Why Sticks Need Therapy (And Sorting) ⚡ TL;DR Need to count just how many triangles you can make from…
The O(n) Club: Minimum Refueling Stops: Out of Gas, Out of Excuses
The O(n) Club: Minimum Refueling Stops—Out of Gas, Out of Excuses ⚡ TL;DR Here’s the deal: you’ve got a half-tank, a desert, and a…
The O(n) Club: Validate Stack Sequences: Because Stack Cheating Isn’t a Sport
The O(n) Club: Validate Stack Sequences — Because Stack Cheating Isn’t a Sport ⚡ TL;DR Given two lists—one is the push parade, the other is…
The O(n) Club: Intersection of Two Arrays: When HashSets Save Your Sanity (and Your CPU)
The O(n) Club: Intersection of Two Arrays — When HashSets Save Your Sanity (and Your CPU) ⚡ TL;DR You want all unique elements from both…
The O(n) Club: The 2D Prefix Sum – Stop Hating Matrix Math (and Yourself)
The O(n) Club: The 2D Prefix Sum – Stop Hating Matrix Math (and Yourself) ⚡ TL;DR Quit writing those nested loops for every sum in a matrix.…
The O(n) Club: Two City Scheduling: Greed, Sorting, and Not Getting Yelled At By Accounting
The O(n) Club: Two City Scheduling—Greed, Sorting, and Not Getting Yelled At By Accounting ⚡ TL;DR Got an even number of people and two…