The O(n) Club: Binary Tree Level Order Traversal II – Boss Mode Unlocked
The O(n) Club: Binary Tree Level Order Traversal II – Boss Mode Unlocked ⚡ TL;DR Need to traverse a tree from leaf to root, level by level?…
The O(n) Club: Letter Case Permutation — Brute Force Meets Java’s Fashion Police
The O(n) Club: Letter Case Permutation — Brute Force Meets Java’s Fashion Police ⚡ TL;DR You get a string. For every letter, you swap its case…
The Mutex Club: Java Runnable—Secret Weapon or Time Bomb?
Key Insights # Runnable 101 Runnable is Java’s simplest concurrency interface: one method—run()—and no return value. Throw it at a Thread or…
The Mutex Club: Mastering Java’s Callable Without Breaking Production
Ever triggered a background task only to watch the logs implode? Java’s Callable<T> is your asynchronous sidekick—until it isn’t.…
The O(n) Club: Longest Univalue Path: When Trees, Edges, and Your Patience All Snap
The O(n) Club: Longest Univalue Path — When Trees, Edges, and Your Patience All Snap ⚡ TL;DR Find the longest path—counted in edges, not…
The O(n) Club: Valid Palindrome: Why Your String Doesn’t Care About Punctuation
The O(n) Club: Valid Palindrome – Why Your String Doesn’t Care About Punctuation ⚡ TL;DR Check if a string’s a palindrome, but ignore…
The Mutex Club: Future-Proofing – Genius Move or Disaster?
The Mutex Club: Future-Proofing – Genius Move or Disaster? ## TL;DR Future-proofing can be your engineering superpower or a one-way ticket to…
The Mutex Club: Mastering Java’s newScheduledThreadPool()
What newScheduledThreadPool() Actually Does When you summon Executors.newScheduledThreadPool(int corePoolSize), Java spins up a…
The O(n) Club: Longest String Chain — The O(n) Club Edition
The O(n) Club: Longest String Chain — The Interview Jenga That Breaks Spirits ⚡ TL;DR Find the biggest possible chain where each word is built…
The O(n) Club: Score of Parentheses—Where Mildly Annoying Brackets Become Mathematical Fireworks
The O(n) Club: Score of Parentheses—Where Mildly Annoying Brackets Become Mathematical Fireworks ⚡ TL;DR Don’t (re)curse yourself! You…