Divisible and Non-divisible Sums Difference (LeetCode Problem 2894)

In this video, we dive into an elegant LeetCode problem (#2894) that transforms from a simple O(n) solution to a beautiful O(1) mathematical approach. We'll explore how basic arithmetic can optimize a seemingly straightforward problem by orders of magnitude, turning linear time complexity into constant time. 📌 What You'll Learn: ✅ How to solve the "Difference of Sums" problem with a naive O(n) approach ✅ The mathematical derivation for an optimized O(1) solution ✅ How to calculate sums of divisible and non-divisible numbers using formulas ✅ Visual proof of the triangular number formula n(n+1)/2 ✅ Step-by-step assembly of the final optimized Python function 🎥 Animated with Manim: Transforming mathematical concepts into clear, engaging visual explanations. 🔗 Manim Community: [https://www.manim.community/](https://www.manim.community/) 💡 Love algorithms, mathematical optimization, or elegant coding solutions? Like, subscribe, and hit the bell (🔔) for more algorithm visualization content! 📌 Video Chapters: 0:00 - Problem Introduction 0:29 - Naive O(n) Solution Analysis 1:10 - Mathematical Visualization: Sum of 1 to n 1:56 - Deriving the Triangular Number Formula 2:55 - Calculating Divisible Sums 4:20 - Calculating Non-Divisible Sums 4:49 - Assembling the O(1) Solution 5:22 - Final Optimized Python Code 🔗 Problem Link: [https://leetcode.com/problems/divisible-and-non-divisible-sums-difference/description/] 🔖 Tags: #leetcode #algorithm #algorithms #datastructures #python #optimization #mathematics #manim #codinginterview #timecomplexity #bigo #programming #visualproof #programming #computerscience #arithmetic