The O(n) Club: First Unique Character in a String—How to Outsmart a Classic Interview Trap
The O(n) Club: First Unique Character in a String—How to Outsmart a Classic Interview Trap ⚡ TL;DR You want the index of the first…
The O(n) Club: Happy Number — When Integers Need Therapy
The O(n) Club: Happy Number — When Integers Need Therapy ⚡ TL;DR Take a number. Replace it with the sum of the squares of its digits. Repeat.…
The O(n) Club: Clone Graph (LeetCode 133) Without Spawning Infinite Twins
The O(n) Club: Clone Graph (LeetCode 133) Without Spawning Infinite Twins ⚡ TL;DR You’ve got a connected undirected graph, and you need to…
The O(n) Club: Find All Anagrams in a String: Java-Only, No Permutation Panic
The O(n) Club: Find All Anagrams in a String: Java-Only, No Permutation Panic ⚡ TL;DR You get a pattern. You get a string. Find every place…
The O(n) Club: Linked List Cycle II — Get Over Yourself and Find the Actual Cycle Start
The O(n) Club: Linked List Cycle II — Get Over Yourself and Find the Actual Cycle Start ⚡ TL;DR You’re over here detecting cycles like it’s a…
The O(n) Club: Partition Labels: Don’t Split Before the Party’s Over
The O(n) Club: Partition Labels—Don’t Split Before the Party’s Over ⚡ TL;DR You want to split a string into as many parts as possible so that…
The O(n) Club: Trie (Prefix Tree): Where Your Prefix Issues Go To Die
The O(n) Club: Trie (Prefix Tree): Where Your Prefix Issues Go To Die ⚡ TL;DR Tries, aka prefix trees, are the go-to when you want to answer…
The O(n) Club: Linked List Cycle Detection, or Why Tortoises Win at Java
The O(n) Club: Linked List Cycle Detection, or Why Tortoises Win at Java ⚡ TL;DR Is your linked list accidentally hosting the world’s…
The O(n) Club: Word Ladder (LeetCode 127): BFS Wizardry Meets Word Jenga
The O(n) Club: Word Ladder (LeetCode 127): BFS Wizardry Meets Word Jenga ⚡ TL;DR Turn beginWord into endWord, one letter per move, using only…
The O(n) Club: Copy List with Random Pointer – How to Not Clone a Dumpster Fire
The O(n) Club: Copy List with Random Pointer – How to Not Clone a Dumpster Fire ⚡ TL;DR Linked list problem but with a spicy random pointer:…