public class Solution
extends Object
106 - Construct Binary Tree from Inorder and Postorder Traversal\.
Medium
Given two integer arrays `inorder` and `postorder` where `inorder` is the inorder traversal of a binary tree and `postorder` is the postorder traversal of the same tree, construct and return _the binary tree_.
**Example 1:**
**Input:** inorder = [9,3,15,20,7], postorder = [9,15,7,20,3]
**Output:** [3,9,20,null,null,15,7]
**Example 2:**
**Input:** inorder = [-1], postorder = [-1]
**Output:** [-1]
**Constraints:**
* `1 <= inorder.length <= 3000`
* `postorder.length == inorder.length`
* `-3000 <= inorder[i], postorder[i] <= 3000`
* `inorder` and `postorder` consist of **unique** values.
* Each value of `postorder` also appears in `inorder`.
* `inorder` is **guaranteed** to be the inorder traversal of the tree.
* `postorder` is **guaranteed** to be the postorder traversal of the tree.