Math

The O(n) Club: Add Binary Strings—Manual Labor For Digital Geniuses ⚡ TL;DR Add two binary strings and return the sum as (surprise!) a binary…

The O(n) Club: Palindrome Number—Mirror, Mirror on My Integer (No Strings, No Magic) ⚡ TL;DR You want to check if a number looks the same…

The O(n) Club: Perfect Squares Problem—Counting Squares Without Losing Yours ⚡ TL;DR Given a number n, find the minimum count of perfect…

The O(n) Club: Reverse Integer Without Getting Fired ⚡ TL;DR Flip the digits of a 32-bit signed integer using only math—string hacks get you…

The O(n) Club: Unique Binary Search Trees—Or, Why Catalan Numbers Rule the Forest ⚡ TL;DR Want to know how many different BSTs you can make…

The O(n) Club: Unique Paths—How Many Ways Can a Robot Survive the Grid? ⚡ TL;DR Counting how many ways a robot can go from the top-left to…

The O(n) Club: Climbing Stairs — Fibonacci, But With Calves of Steel ⚡ TL;DR Climbing n stairs, taking 1 or 2 steps at a time?…