Longest Substring Without Repeating Characters (LeetCode 3) | 🔥 DSA Java Placement Course

In this video, we will solve one of the most popular string problems asked in coding interviews — Longest Substring Without Repeating Characters (LeetCode 3). This question is a classic example of how to use the Sliding Window Technique and HashMap efficiently in Java. ◾◼️ Useful Notes & Courses Links◼️◾ 👉🏻 Free Notes : https://smartprogramming.in/tutorials/ 👉🏻 Free Courses : https://smartprogramming.in/free-online-courses 👉🏻 Java Programming Course + Certificate (Upto 80% off) : https://smartprogramming.in/premium-courses ◾◼️ Youtube Free Playlists ◼️◾ 👉🏻 Core Java : https://www.youtube.com/playlist?list=PLlhM4lkb2sEhfuXL-2BDrJ67WkUdQ2v9b 👉🏻 Core Java - Java SE 21 Version (2025) : https://www.youtube.com/playlist?list=PLlhM4lkb2sEjtoPRP2AfVGJWFoltwtDdx 👉🏻 Data Structures & Algorithms (DSA) : https://www.youtube.com/playlist?list=PLlhM4lkb2sEjyqHABtdVXppkbN7-SDJ_- 👉🏻 Advance Java : https://www.youtube.com/playlist?list=PLlhM4lkb2sEjVsbbZ_kiixY5CcR84IQUg 👉🏻 Spring Framework : https://www.youtube.com/playlist?list=PLlhM4lkb2sEgJDGj2zOJnp0y5A5E6li1k 👉🏻 Springboot : https://www.youtube.com/playlist?list=PLlhM4lkb2sEhcrb1-4eyDE-rXnGNVYsek 👉🏻 Git & GitHub : https://www.youtube.com/playlist?list=PLlhM4lkb2sEijMDkb-AEUO-kzDdqxMuxS 👉🏻 Python : https://www.youtube.com/playlist?list=PLlhM4lkb2sEjIWihTdQ3Z1ifaYVHAk5YC ◾◼️ Call & Whats App ◼️◾ 📞 Call : +91 62838-30308 ; +91 98887-55565 ✆ Whats App 1 : https://wa.me/916283830308 ✆ Whats App 2 : https://wa.me/919888755565 ◾◼️ Connect With Us On ◼️◾ 👉🏻 Facebook Page : https://www.facebook.com/smartprogramming.india 👉🏻 Instagram : https://www.instagram.com/smart_programming 👉🏻 Telegram : https://t.me/smart_programming_deepak 👉🏻 Whats App : https://www.whatsapp.com/channel/0029Va6n2Gs42Dckpa2T1U1i 👉🏻 Amazon Store : https://www.amazon.in/shop/smartprogramming You’ll learn: ✔ What the problem is asking ✔ Step-by-step explanation of the logic ✔ How the sliding window expands and shrinks ✔ Updating window boundaries using HashMap ✔ How to write the clean and optimized Java solution ✔ Time and space complexity ✔ Tips for cracking similar string and window problems in technical interviews Whether you’re preparing for placements, internships, coding interviews, or learning DSA in Java, this video will help you master the concept clearly. ⭐ Timestamps 00:00 – Introduction 00:12 – Longest Substring Problem Explanation 01:52 – Longest Substring Problem Solved using Sliding Window Concept 14:27 – Longest Substring Problem Solved using HashMap 📘 Topics Covered in This Video ✔ Longest Substring Without Repeating Characters ✔ LeetCode 3 Java Solution ✔ Sliding Window Algorithm ✔ Variable Size Sliding Window ✔ HashMap Based Approach ✔ Java String Interview Questions ✔ DSA Java Placement Course ✔ Frequently Asked Interview Problems ✔ Coding Interview Preparation ✔ Most Asked String Problems 🔥 This video is perfect for: ✔ Students preparing for placements ✔ Candidates appearing for technical interviews ✔ Beginners learning DSA in Java ✔ Anyone solving LeetCode problems ✔ Those who want a clear explanation of sliding window 🧑‍💻 HashTags (SEO Friendly) #dsa #java #leetcode #slidingwindow #codinginterview #datastructures #placements #stringproblems #leetcode3 #javaprogramming