Return any binary tree that matches the given preorder and postorder traversals. Values in the traversals pre and post are distinct positive integers. Example 1: Input: pre = [1,2,4,5,3,6,7], post = [4,5,2,6,7,3,1] Output: [1,2,3,4,5,6,7] Note: 1 <= pre.length == post.length <= 30 pre[] and post[] are both permutations of 1, 2, ..., pre.length. It is guaranteed an answer exists. If there exists multiple answers, you can return any of them.