Neetcode: Construct Binary Tree from Preorder and Inorder Traversal

Instructions

You are given two integer arrays preorder and inorder.

• preorder is the preorder traversal of a binary tree
• inorder is the inorder traversal of the same tree
• Both arrays are of the same size and consist of unique values.

Rebuild the binary tree from the preorder and inorder traversals and return its root.

Example 1:

Input: preorder = [1,2,3,4], inorder = [2,1,3,4]

Output: [1,2,3,null,null,null,4]

Example 2:

Input: preorder = [1], inorder = [1]

Output: [1]

Constraints:

• 1 <= inorder.length <= 1000
• inorder.length == preorder.length
• -1000 <= preorder[i], inorder[i] <= 1000