Array

The O(n) Club: 4Sum II — When Hashmaps Save You from Loop Purgatory ⚡ TL;DR Given four integer arrays, count (i, j, k, l) such that nums1[i] +…

The O(n) Club: Merge Sorted Arrays — Why Going Backwards Is Forwards Thinking ⚡ TL;DR Trying to merge two already sorted arrays (LeetCode 88)…

The O(n) Club: Find the Town Judge—Or the Search for the Ultimate Influencer ⚡ TL;DR You’re looking for the one person in town everyone…

The O(n) Club: Find the Town Judge (LeetCode 997) — Java Edition for Trust Issues ⚡ TL;DR This problem is about sniffing out that one person…

The O(n) Club: Find K Pairs with Smallest Sums — Now with 93% Less Suffering ⚡ TL;DR Find k pairs with the smallest sums by using a…

The O(n) Club: Maximum XOR of Two Numbers in an Array: Ditch Loops, Grab Bits ⚡ TL;DR Find the biggest XOR between any two numbers in an…

The O(n) Club: Pairs of Songs With Total Durations Divisible by 60 — Now That’s What I Call Modulo! ⚡ TL;DR If you want to pair up songs so…

The O(n) Club: Maximum Profit in Job Scheduling – How Not to Overbook Your Calendar (or Lose Your Mind) ⚡ TL;DR You’re given jobs with a…

The O(n) Club: Russian Doll Envelopes—Where Sorting Actually Makes You Look Smart ⚡ TL;DR Find the most envelopes that fit inside each other,…

The O(n) Club: Russian Doll Envelopes—How to Stuff Smarter, Not Harder ⚡ TL;DR Goal: Nest as many envelopes (each: width, height) as possible…