Construct Binary Tree from Preorder and Inorder Traversal

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_.   **Example 1:** **Input:** preorder = [3,9,20,15,7], inorder = [9,3,15,20,7] **Output:** [3,9,20,null,null,15,7] ``` **Example 2:** **Input:** preorder = [-1], inorder = [-1] **Output:** [-1] ```   **Constraints:** - `1 <= preorder.length <= 3000` - `inorder.length == preorder.length` - `-3000 <= preorder[i], inorder[i] <= 3000` - `preorder` and `inorder` consist of **unique** values. - Each value of `inorder` also appears in `preorder`. - `preorder` is **guaranteed** to be the preorder traversal of the tree. - `inorder` is **guaranteed** to be the inorder traversal of the tree.