DSA Python 2025 – Word Ladder | BFS for Shortest Transformation | Leetcode 127 – Part 129 [Hindi]

🚀 Welcome to Part 129 of Code & Debug’s DSA Python Course 2025!

In this lecture, we solve Leetcode 127: Word Ladder, where we find the shortest transformation sequence from beginWord to endWord by changing one character at a time — and every intermediate word must be in the given word list. We solve it using an efficient Breadth-First Search (BFS) approach.

📚 What you’ll learn in this video:
✅ Understanding the word transformation graph
✅ BFS logic to find the shortest path
✅ Dynamic generation of all possible one-character transformations
✅ Using a set for fast lookups and removal
✅ Full dry run, time and space complexity analysis

💡 Why is this important?
This problem is a textbook example of graph BFS in disguise. It teaches you how to model non-obvious problems as graphs — a crucial skill for interviews and real-world applications involving transformations, routing, and state-space exploration.

👉 Practice the problem on Leetcode:
🔗 https://leetcode.com/problems/word-ladder/

👉 Refer to the article for better understanding:
📌 https://codeanddebug.in/blog/word-ladder-leetcode-127/

👉 📄 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

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