Reconstruct a binary tree from traversals

## Coding: Build a Binary Tree from Two Traversals You are given two integer arrays representing traversals of the **same** binary tree: - `preorder`: node order is **root → left → right** - `inorder`: node order is **left → root → right** All values are **unique**. ### Task Reconstruct the binary tree and return its root node. ### Input - `preorder`: length `n` (1 ≤ n ≤ 10^5) - `inorder`: length `n` - Values are unique integers. ### Output - Return the root of the reconstructed binary tree (using a standard `TreeNode { val, left, right }` structure). ### Example - `preorder = [3, 9, 20, 15, 7]` - `inorder = [9, 3, 15, 20, 7]` The reconstructed tree is: - root = 3 - left child = 9 - right subtree rooted at 20 with children 15 and 7 ### Notes - Assume the input is valid (both traversals come from one binary tree). - Your solution should be efficient for large `n`.