Construct Binary Tree from Inorder and Postorder Traversal

Given inorder and postorder traversals of a tree with unique values, construct the tree and return its level-order array.

Examples
Input: [[9,3,15,20,7],[9,15,7,20,3]]
Output: [3,9,20,null,null,15,7]
Hints

Construct Binary Tree from Inorder and Postorder Traversal

Given inorder and postorder traversals of a tree with unique values, construct the tree and return its level-order array.