Medium
Quiz
#105 Construct Binary Tree from Preorder and Inorder Traversal
APPROACH
You are given two integer arrays: preorder containing the preorder traversal of a binary tree, and inorder containing the inorder traversal of the same tree. Use both arrays to reconstruct and return the original 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]
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What is the optimal approach for this problem?