Given a Binary Tree. Find the Zig-Zag Level Order Traversal of the Binary Tree.

Input:
First line of input contains the number of test cases T. For each test case, there will be only a single line of input which is a string representing the tree as described below: 

  1. The values in the string are in the order of level order traversal of the tree where, numbers denotes node values, and a character “N” denotes NULL child.

  2. For example:


    For the above tree, the string will be: 1 2 3 N N 4 6 N 5 N N 7 N

Output:
For each test case print on a new line space-separated all the nodes of the tree in ZigZag manner.

Your Task:
You don't need to read input or print anything. Your task is to complete the function zigZagTraversal() which takes the root node of the Binary Tree as its input and returns a list containing the node values as they appear in the Zig-Zag Level-Order Traversal of the Tree.
For Example: For the below binary tree the zigzag order traversal will be 1 3 2 7 6 5 4.

Expected Time Complexity: O(N).
Expected Auxiliary Space: O(N).

Constraints:
1 <= T <= 100
1 <= N <= 104

Example:
Input:
2
3 2 1
7 7 9 8 8 6 N 10 9
Output:
3 1 2
7 9 7 8 8 6 9 10

Explanation:
Testcase 1: Given tree is
                         3
                      /       \
                    2        1
Hence the zigzag traversal will be 3 1 2.
Testcase 2: Given tree is 
                           7
                       /        \
                    9           7
                /        \      /     \
               8        8    6     N
            /      \
          10     9  
Hence the zigzag traversal will be 7 9 7 8 8 6 9 10.

Note:The Input/Ouput format and Example given are used for system's internal purpose, and should be used by a user for Expected Output only. As it is a function problem, hence a user should not read any input from stdin/console. The task is to complete the function specified, and not to write the full code.

** For More Input/Output Examples Use 'Expected Output' option **

Contributor: Harshit Sidhwa
Author: harshitsidhwa


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