#t463. 扩展二叉树
扩展二叉树
Extended Binary Tree
Problem Background
Special for beginners, ^_^
Problem Description
Because none of the pre-order, in-order, or post-order sequences alone can uniquely determine a binary tree, we process the tree as follows: we pad every empty (null) node with a ., as shown in the figure.
We call the resulting tree the extended binary tree of the original one; the pre-order and post-order sequences of an extended binary tree uniquely determine the binary tree.
You are given the pre-order sequence of an extended binary tree; output its in-order and post-order sequences.

Input Format
One string, made of uppercase letters and ., giving the pre-order sequence of the extended binary tree. Its length is less than .
Output Format
Print two lines: the first is the in-order sequence, the second is the post-order sequence.
Sample Input
ABD..EF..G..C..
Sample Output
DBFEGAC
DFGEBCA
Constraints
Length of the string .
Time limit s, memory KiB per test case.
Hint
- The
.marks an empty subtree. In pre-order traversal, when you read a.you return (that branch is null); otherwise create the node and recurse left then right. - Reconstruct the tree recursively, then output in-order and post-order.