L23 Construct Binary Tree from Inorder & Preorder Traversal | O(n) Optimal Solution | GFG + LeetCode

Master one of the most important Binary Tree interview problems: Construct Tree from Inorder & Preorder Traversal. In this video, you'll learn the optimal O(n) approach to reconstruct a binary tree using preorder and inorder traversals. This problem is frequently asked in coding interviews at top product companies and is available on both GeeksforGeeks and LeetCode. 📌 Problem Overview Given the Inorder and Preorder traversal arrays of a binary tree, construct the original binary tree and return its root. 🚀 What you'll learn Binary Tree construction from traversals Relationship between Inorder & Preorder HashMap-based optimized solution Recursive tree building strategy Step-by-step dry run with example ⏱ Complexity Optimized: O(n) Time Space: O(n) 🎯 Difficulty MEDIUM 🏷 Topics Binary Tree Tree Recursion HashMap 💼 Frequently Asked In Amazon • Microsoft • Accolite If this video helped you, don't forget to Like 👍, Subscribe 🔔, and Share for more DSA interview problems! #dsa #geeksforgeeks #leetcode #binarytree #trees #recursion #java #codinginterview #programming #algorithms