Given two integer arrays preorder and inorder where preorder is the preorder traversal of a binary tree and inorder is the inorder traversal of the same tree, construct and return the binary tree.

• Two integer arrays preorder and inorder.

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