LeetCode 205 | Isomorphic Strings | Python Two-Way Mapping | AlgoYogi

Welcome to AlgoYogi! 🚀 Start Your Smart Coding Prep at 👉 https://algoyogi.io In this video, we solve **LeetCode 205: Isomorphic Strings** using Python and a robust **two-way hash map** strategy. Definition: Two strings s and t are isomorphic if characters in s can be replaced to transform it into t, with a one-to-one and onto mapping. Replacements must be consistent and preserve order. Approach: - Use two dictionaries: • mapST: maps characters from s to t • mapTS: maps characters from t to s - Iterate over pairs (a, b) from s, t: • If a is already in mapST and mapST[a] != b → return False • If b is already in mapTS and mapTS[b] != a → return False • Otherwise, record mapST[a] = b and mapTS[b] = a - If no conflict arises, return True Examples: - s = "egg", t = "add" → true - s = "foo", t = "bar" → false - s = "paper", t = "title" → true --- ### ⏱ Timestamps 0:00 Introduction 0:20 Problem Statement 0:30 Mapping Idea & Two Dictionaries 6:30 Python Code Walkthrough 11:00 Time & Space Complexity --- ### Why Watch? - Master **bidirectional mapping** to enforce one-to-one character correspondence - Learn how to handle edge cases like repeated characters or conflicting mappings - Interview-ready solution with **O(n)** time and space efficiency #LeetCode #IsomorphicStrings #Python #TwoWayMapping #HashMaps #AlgoYogi