题目描述

A Binary Search Tree (BST) is recursively defined as a binary tree which has the following properties:
The left subtree of a node contains only nodes with keys less than the node's key.
The right subtree of a node contains only nodes with keys greater than or equal to the node's key.
Both the left and right subtrees must also be binary search trees. 
Given the structure of a binary tree and a sequence of distinct integer keys, there is only one way to fill these keys into the tree so that the resulting tree satisfies the definition of a BST.  You are supposed to output the level order traversal sequence of that tree.  The sample is illustrated by Figure 1 and 2.

输入描述:

Each input file contains one test case.  For each case, the first line gives a positive integer N (<=100) which is the total number of nodes in the tree.  The next N lines each contains the left and the right children of a node in the format "left_index right_index", provided that the nodes are numbered from 0 to N-1, and 0 is always the root.  If one child is missing, then -1 will represent the NULL child pointer.  Finally N distinct integer keys are given in the last line.

输出描述:

For each test case, print in one line the level order traversal sequence of that tree.  All the numbers must be separated by a space, with no extra space at the end of the line.

输入例子:

9
1 6
2 3
-1 -1
-1 4
5 -1
-1 -1
7 -1
-1 8
-1 -1
73 45 11 58 82 25 67 38 42

输出例子:

58 25 82 11 38 67 45 73 42