LeetCode 133: Clone Graph | DFS with Hash Map in JavaScript

In this video, I solve LeetCode 133: Clone Graph using a depth-first search (DFS) approach with a Map to track visited nodes in JavaScript.

This problem is all about making a deep copy of a connected graph, even when cycles or shared nodes are involved. I explain how DFS works to traverse each node and how a hash map (or JS Map) prevents infinite loops by remembering what’s already cloned.

This solution is efficient, interview-safe, and easily extendable to BFS if needed.

P.S. I said children a lot, I mean neighbors.

What You’ll Learn:
✅ How to clone a graph using DFS
✅ Why a map is needed to track visited/cloned nodes
✅ JavaScript class-based graph representation
✅ Time and space complexity explained

Chapters:
0:00 - Question
1:50 - Solution Explanation
6:30 - Code

💬 Want to see the BFS version using a queue instead of recursion? Let me know in the comments!

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