The O(n) Club: Invert Binary Tree – Mirror Mayhem and Recursive Therapy
The O(n) Club: Invert Binary Tree – Mirror Mayhem and Recursive Therapy ⚡ TL;DR Take a binary tree and swap every left and right…
The O(n) Club: Preorder-Inorder Tree Rebuilds — Actually Fun, Actually Linear
The O(n) Club: Preorder-Inorder Tree Rebuilds — Actually Fun, Actually Linear ⚡ TL;DR Want to turn two scrambled traversals back into a…
The O(n) Club: Regular Expression Matching — When ‘.’ and ‘*’ Run the Show
The O(n) Club: Regular Expression Matching — When ‘.’ and ‘*’ Run the Show ⚡ TL;DR Match string s against pattern p…
The O(n) Club: Edit Distance — When Strings Need Surgery (LeetCode 72)
The O(n) Club: Edit Distance — When Strings Need Surgery (LeetCode 72) ⚡ TL;DR How do you transform one string into another with as few…
The O(n) Club: Palindrome Linked List: Sanity-Check Edition—Because Lists Deserve Symmetry Too
The O(n) Club: Palindrome Linked List—Sanity-Check Edition ⚡ TL;DR Want to see if your singly linked list reads the same from both ends, but…
The O(n) Club: Rotate Image Without Losing Your Mind (LeetCode 48)
The O(n) Club: Rotate Image Without Losing Your Mind (LeetCode 48) ⚡ TL;DR Rotate your n x n matrix 90° in-place by: (1) transposing (swap…
The O(n) Club: Unique Paths—How Many Ways Can a Robot Survive the Grid?
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: Majority Element — The Array’s Unbeatable Bully
The O(n) Club: Majority Element — The Array’s Unbeatable Bully ⚡ TL;DR The Majority Element is the number that turns your array into a…
The O(n) Club: Linked Lists Intersection — Y-Junctions, Off-By-One Fails, and Pointer Shenanigans
The O(n) Club: Linked Lists Intersection — Y-Junctions, Off-By-One Fails, and Pointer Shenanigans ⚡ TL;DR Given two singly linked lists that…
The O(n) Club: Move Zeroes — In-Place, In-Order, In-Interview Panic
The O(n) Club: Move Zeroes — In-Place, In-Order, In-Interview Panic ⚡ TL;DR Move all zeroes to the end of your array—don’t use extra space,…