Create Binary Tree From Descriptions | LeetCode 2196 | Medium | Complete Explanation

In this video, we solve LeetCode 2196: Create Binary Tree From Descriptions using an efficient HashMap + Set approach. You'll learn: ✅ How to construct a binary tree from parent-child relationships ✅ How to identify the root node efficiently ✅ Why a HashMap is the perfect data structure for this problem ✅ Step-by-step dry run with example input ✅ Optimal solution with detailed explanation ✅ Interview tips and common pitfalls Problem Statement You are given a list of descriptions where each entry contains: Parent Node Child Node Whether the child is a left or right child Your task is to construct the binary tree and return its root node. Key Concepts Covered Binary Trees Tree Construction HashMap HashSet Parent-Child Relationships Graph to Tree Conversion DFS/BFS Understanding Optimal Approach Create nodes using a HashMap. Connect parent and child nodes. Track all child nodes in a set. The node that never appears as a child is the root. Time & Space Complexity ✅ Time Complexity: O(n) ✅ Space Complexity: O(n) This is a popular interview problem that tests your understanding of trees, mappings, and efficient data structure usage. 🔥 Perfect for coding interview preparation at Google, Amazon, Microsoft, Meta, Netflix, and other top tech companies. If you found this explanation helpful, don't forget to Like 👍, Share 🚀, and Subscribe 🔔 for more LeetCode solutions and System Design content. Hashtags #leetcode,#leetcode2196,#binarytree,#treeconstruction,#trees,#hashmap,#hashset,#datastructures,#algorithms,#codinginterview,#softwareengineer,#programming,#java,#cpp,#python,#javascript,#competitiveprogramming,#interviewpreparation,#sde,#google,#amazon,#microsoft,#meta,#netflix,#leetcodeproblem,#leetcodeexplained,#coding,#tech,#dsa,#mediumleetcode