Complete the function to print spiral order traversal of a tree. For below tree, function should print 1, 2, 3, 4, 5, 6, 7.


 

 

Input Format:
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 Format:
The function should print level order traversal in spiral form.

Your Task:
The task is to complete the function printSpiral() which prints the elements in spiral form of level order traversal. The newline is automatically appended by the driver code.

Constraints:
1 <= T <= 30
1 <= Number of nodes <= 105
1 <= Data of a node <= 105

Example:
Input:

2
1 3 2  
10 20 30 40 60 
Output:

1 3 2
10 20 30 60 40 

Explanation:
Testcase1: The tree is
        1
     /      \
   3       2
So, the spiral level order would be 1 3 2
Testcase2: The tree is
                           10
                        /        \
                     20         30
                  /       \
               40       60
So, the spiral level order would be 10 20 30 60 40

 

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: Amit Khandelwal, Harshit Sidhwa
Author: Shubham Joshi 1


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