Given a binary tree, return the postorder traversal of its nodes' values. For example:Given binary tree {1,#,2,3}, 1 \ 2 / 3 return [3,2,1]. Note: Recursive solution is trivial, could you do it iteratively? 1.递归算法的递归定义是: 若二叉树为空,则遍历结束:否则⑴ 后序遍历左子树(递归调用…