LeetCode 15: 3Sum JavaScript Explained | Brute Force to Optimal Two-Pointer

LeetCode 15: 3Sum JavaScript | Brute Force to Optimal O(n²) Solution Master the *3Sum* problem on LeetCode (Problem #15) in JavaScript! In this comprehensive tutorial, I break down the complete step-by-step transition from the *Brute Force O(n³)* nested-loops approach to the *Optimal O(n²)* Two-Pointer technique. Whether you are preparing for technical coding interviews or strengthening your Data Structures and Algorithms (DSA) foundation in JavaScript, this video covers everything from constraint analysis and logic visualization to dry runs and clean JavaScript implementation. ⏱️ Timestamps 00:00:00 - Introduction & Problem Constraints 00:02:25 - Brute Force Approach (Concept & Visual Logic) 00:13:36 - Optimal Two-Pointer Strategy (Concept & Visual Logic) 00:25:42 - Time Complexity Analysis (O(n³) vs. O(n²)) 00:26:36 - JavaScript Implementation: Brute Force Code 00:31:30 - JavaScript Implementation: Optimal Code & Outro 🛠️ Interactive Whiteboard & Resources Interactive Whiteboard Diagram: https://whiteboard-ruby-ten.vercel.app/ LeetCode Problem Link: https://leetcode.com/problems/3sum/ 💡 What You Will Learn 1. Understanding Constraints: How array size (N) dictates whether an O(n³) solution will trigger Time Limit Exceeded (TLE). 2. Brute Force Logic: Generating all unique triplets using three pointers and handling duplicate triplets. 3. Two-Pointer Optimization: Sorting the array to convert 3Sum into a modified 2Sum problem, effectively reducing the time complexity to O(n²). 4. Duplicate Handling: Skipping identical elements efficiently to ensure all returned triplets are unique. 📩 Contact & Connect Email: [anubhav10670@gmail.com](mailto:anubhav10670@gmail.com) 🏷️ SEO Tags & Keywords LeetCode 15, 3Sum JavaScript, 3Sum Brute Force to Optimal, LeetCode 15 JavaScript Solution, Two Pointer Approach JavaScript, 3Sum Two Pointer Method, 3Sum Time Complexity, JavaScript Data Structures and Algorithms, 3Sum Problem LeetCode JS, Coding Interview Preparation JavaScript