说明：  一般来说，给定二叉树的先序遍历序列和后序遍历序列，并不能确定唯一确定该二叉树。比如图中的两棵二叉树，虽然它们是不同二叉树，但是它们的先序、后序遍历序列都是相同的。 但是对于“真二叉树”（每个内部节点都有两个孩子的二叉树），给定它的先序、后序遍历序列足以完全确定它的结构。 将二叉树的n个节点用[1, n]内的整数进行编号，输入一棵真二叉树的先序、后序遍历序列，请输出它的中序遍历序列。
(There are n students in an English class. Each student has his own integer student number. Note that this time due to the expansion of the course, the number of students is very large. Now this English course is ready for the final examination. The form of the examination is: each student has a conversation with the teacher for a period of time. The teacher decided to make use of the round table outside the classroom and determine the examination order randomly according to the following method: the first arriving student will sit down at any position around the round table; after that, each student who arrives will start from the former student and walk around the round table in a counter clockwise direction (the former student is counted as the first person who)