程序输入是一个（扩展）二叉树的先序序列。例如：扩展二叉树先序序列为ab#d##ce###。其中#代表空指针。

编写程序实现二叉树的如下操作：

1） 建立二叉链表

2）二叉树的先序、中序、后序遍历

3）求解二叉树的叶子结点个数

4）将二叉树中所有结点的左、右子树相互交换 -Program input is a (extended) binary tree inorder sequence. For example: the first order extended binary tree sequence is ab# d## ce###. Where# null pointer. Programming to achieve binary tree as follows: 1) the establishment of binary list 2) the first order binary tree, in order, the order of traversal 3) solve the binary tree leaf node number 4) binary tree All nodes of the left and right subtree exchange