DSA SERIES | Linked List | LECTURE 11 | LEETCODE PROBLEM 142

🚀 DSA SERIES | Lecture 11 | LeetCode 142: Linked List Cycle IIWelcome to the eleventh lecture of our Data Structures & Algorithms (DSA) Series! In Lecture 7, we learned how to detect a loop; today, we take it a step further by finding exactly where that loop begins. We are deep-diving into LeetCode 142 - Linked List Cycle II. This problem requires a two-stage approach to master the "Cycle Start Principle". 💡 In this lecture, you’ll learn: Stage 1: Detect Cycle: Re-applying Floyd’s Tortoise and Hare algorithm to confirm the existence of a loop in O(1) space. Stage 2: Find Cycle Start: The mathematical logic behind why resetting one pointer to the head and moving both at the same speed leads them to meet at the cycle's entry point. Mathematical Proof: A simple breakdown of the distance equation that proves this algorithm works every time. Linked List with Cycle Visual: Breaking down the "Nenked Llste" structure to see how nodes connect back to previous indices. O(N) Time Complexity: Ensuring our find is efficient and optimized for high-performance coding rounds.🎯 This is a classic "Phase 2" interview question. Interviewers often ask this immediately after you solve the basic cycle detection problem to test if you truly understand the pointer mathematics. 🔥 Master the math and the logic to solve advanced Linked List problems with ease! 📌 Missed Lecture 10? Watch how to populate Next Right Pointers here: https://youtu.be/Y5DySDsQ3J8?si=XNYSV-bg7leYNnlc. 📌 Next Up: We transition into Stacks and Queues with LeetCode 20: Valid Parentheses! Challenge: If a linked list has 10 nodes and the 10th node points back to the 4th node, what is the length of the cycle? Let me know in the comments! 👇#DSA #DataStructures #Algorithms #LeetCode142 #LinkedListCycle #FloydAlgorithm #TwoPointers #CodingInterview #Programming #Cpp #Java #Python #TechInterview #FullOnCoding #PlacementPreparation