Data Structures and Algorithms with Python | Free DSA with Python Course - DSA Python 2025 - Detect Cycle in Undirected Graph | DFS with Parent Check | GFG - Part 125 [Hindi]

🚀 Welcome to Part 125 of Code & Debug’s DSA Python Course 2025! In this video, we solve the Detect Cycle in an Undirected Graph problem from GeeksforGeeks using a Depth First Search (DFS) approach. We maintain a parent reference to correctly identify cycles without revisiting the edge we came from. 📚 What you’ll learn in this video: ✅ How cycle detection works in undirected graphs ✅ Why we need to track the parent of each node in DFS ✅ Recursive DFS implementation with visited array ✅ Building adjacency list from edge list ✅ Dry run + time and space complexity analysis 💡 Why is this important? This DFS-based approach is a fundamental graph technique used in cycle detection, graph coloring, tree validation, and connected component analysis. It's a frequent topic in coding interviews and online assessments. 👉 Practice the problem on GeeksforGeeks: 🔗 https://www.geeksforgeeks.org/problems/detect-cycle-in-an-undirected-graph/1 👉 Refer to the article for better understanding: 📌 https://codeanddebug.in/blog/detect-cycle-in-an-undirected-graph-using-dfs/ 👉 📄 Access the full YouTube DSA Playlist Sheet (All Questions in Order): 🔗 https://docs.google.com/spreadsheets/d/1AWE15Fy3wD2iqu2vjK_R7cCiuvSsjYQclcdZmHpF66o/edit?usp=sharing 👉 Enroll in this FREE DSA Python course here: 🔗 https://codeanddebug.in/course/master-dsa-with-leetcode 👉 Enroll for Self-Paced Advanced DSA course here: 🔗 https://codeanddebug.in/course/zero-to-hero-python-dsa 🙏 Thank you for supporting Code & Debug! Don’t forget to like, share, and subscribe to our channel. Hit the 🔔 bell icon to stay updated with our latest lectures. #DetectCycleDFS #UndirectedGraph #CycleDetection #GraphDFS #GeeksforGeeks #PythonDSA #DSAPythonCourse #CodeAndDebug #DSA2025 #Part125 #CodingInterviews