Leetcode 42 🔥 Trapping Rain Water | NeetCode 150 Sheet | Java Optimal + Handwritten Dry Run

In this video, we solve Leetcode 42 - Trapping Rain Water from the NeetCode 150 DSA Sheet using Java. Code: https://github.com/studyPlacement/CodeHub/blob/main/Solution42 Neetcode 150 Playlist: https://youtube.com/playlist?list=PLsLlEdtakGozrvhxZsPfvXavXYzX2GUig&feature=shared DP Playlist: https://youtube.com/playlist?list=PLsLlEdtakGoyNROP7uWS9OLLHs9_JluVM&feature=shared Sliding window Playlist: https://youtube.com/playlist?list=PLsLlEdtakGozlKx_L-5PQJO-ua_maQb6R&feature=shared Binary Search Playlist: https://youtube.com/playlist?list=PLsLlEdtakGozNxx5rfRgEW-1DYseLnDbV&feature=shared We use the optimal Two Pointer approach to solve this problem in O(n) time and O(1) space, and explain it with a complete handwritten dry run ✍️ on paper for better understanding. 🔥 What you’ll learn: - Trapping Rain Water logic explained - Two Pointer approach with space optimization - Step-by-step handwritten paper dry run - Clean and efficient Java code walkthrough 📌 Problem Link: https://leetcode.com/problems/trapping-rain-water/ 🎯 Level: Hard 💡 Topics: Array, Two Pointers, Java 👉 Don’t forget to like 👍, share ↗️, and subscribe 🔔 for more handwritten DSA content! #leetcode #neetcode150 #trappingrainwater #dsa #javaprogramming #twopointers #handwrittennotes #placementpreparation #codinginterview Timestamps: 00:00 Introduction 00:18 Problem Statement 01:00 Brute force Approach 08:30 Brute force Code Explained 09:15 Dry run 15:12 Optimized Approach 19:50 Optimized Code Explanation + Dry run 23:15 Optimal Approach 29:30 Optimal code Explanation + Dry run