Day 26: Construct Binary Tree from Preorder & Inorder (LeetCode 105) — Amazon Interview Question! 🚀

Описание: 🎯 Day 26 of My LeetCode Journey | Construct Binary Tree from Preorder and Inorder Traversal (LeetCode 105)

In this video, I solve LeetCode Problem #105 — Construct Binary Tree from Preorder and Inorder Traversal using JavaScript! This is a frequently asked Amazon interview question 🚨 that tests your understanding of tree traversals and recursive tree construction.

🔗 Problem Link: https://leetcode.com/problems/constru...

📌 PROBLEM SUMMARY:
Given two integer arrays preorder and inorder where:

preorder is the preorder traversal of a binary tree
inorder is the inorder traversal of the same tree
Construct and return the binary tree.

✅ Example 1:
Input: preorder = [3,9,20,15,7], inorder = [9,3,15,20,7]
Output: [3,9,20,null,null,15,7]

✅ Example 2:
Input: preorder = [-1], inorder = [-1]
Output: [-1]

💡 KEY CONCEPTS:
✅ Preorder Traversal (Root → Left → Right): First element is always root
✅ Inorder Traversal (Left → Root → Right): Elements before root are in left subtree
✅ HashMap for fast index lookup
✅ Recursive tree construction
✅ Divide and conquer strategy

📊 COMPLEXITY:
• Time: O(n) - visit each node once
• Space: O(n) - recursion stack

🎓 DIFFICULTY: Medium
🏷️ TOPICS: Array, Divide and Conquer, Tree, Binary Tree

🏢 ASKED AT: Amazon, Microsoft, Facebook, Bloomberg

🔥 WHY THIS MATTERS:
This is a classic tree reconstruction problem that appears in Amazon interviews frequently. Understanding how preorder and inorder traversals work together is crucial for many tree-related problems!

💻 JAVASCRIPT SOLUTION:
I'll walk you through the complete JavaScript implementation with detailed explanations!

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📚 MY LEETCODE JOURNEY PLAYLIST:
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• GitHub: https://github.com/ashwinikemshetty
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