LeetCode 433: Minimum Genetic Mutation | Python Solution | BFS Graph Traversal

🧬 In this problem, we need to find the minimum number of mutations required to convert one DNA string to another, given a bank of valid mutations. #leetcode #bfs #graph #mutations #stringmanipulation ⏱️ **Time Complexity**: O(L * N), where L is the length of the gene string and N is the size of the gene bank 🗃️ **Space Complexity**: O(N) ## Timestamps: 00:00 - Understanding problem statement 02:56 - Optimized solution 05:05 - Dry run 06:57 - Big O Notation calculated 07:56 - Python code walk-through 09:41 - Solution analysis - runtime + memory 09:49 - Conclusion ## Key Concepts: - Breadth-First Search (BFS) algorithm - Graph representation of mutation paths - String manipulation in Python - Queue implementation using collections.deque - Shortest path in an unweighted graph ## Main Learning Points: - How to model genetic mutations as a graph problem - Implementing efficient BFS for finding shortest paths - Handling string manipulations effectively in Python - Tracking visited nodes to avoid cycles - Optimizing search space in BFS traversals ## Related Problems: - LeetCode 127: Word Ladder - LeetCode 752: Open the Lock - LeetCode 997: Find the Town Judge - LeetCode 1091: Shortest Path in Binary Matrix ## Target Audience: This video is for intermediate programmers preparing for coding interviews, particularly those focused on graph algorithms and string manipulation problems. ## Prerequisites: - Basic understanding of Python - Familiarity with graph traversal algorithms (BFS/DFS) - Understanding of queue data structure - Basic string manipulation in Python ## Links: 📝 LeetCode problem: https://leetcode.com/problems/minimum-genetic-mutation/ 💻 Solution code: https://leetcode.com/problems/minimum-genetic-mutation/solutions/7080750/minimum-genetic-mutation-solution-in-pyt-hmd0 ## Additional Tips: - Pay special attention to the valid mutations check - this is where many solutions become inefficient - BFS is preferred over DFS here because we're looking for the minimum number of mutations - Consider how to efficiently generate all possible mutations without redundant checks ## Call to Action: 🔔 If you found this solution helpful, please like and subscribe for more LeetCode solutions! Share your approach or questions in the comments below. Do you have a specific optimization for this problem? I'd love to hear your thoughts! #codinginterview #pythonsolution #algorithmsanddata