Reverse a Doubly Linked List

Given a doubly linked list of positive integers with size 'N', reverse the list and return the head of the modified list.

Explanation:

A doubly linked list allows traversal in both directions, forward and backward.

Input:

The input begins with an integer 'T', representing the number of test cases.
Each test case comprises elements of the doubly linked list, separated by a space and terminated by -1, indicating the end of the list.

Output:

For each test case, output the elements of the reversed list, separated by a space and followed by -1.
Provide the output of each test case in a separate line.

Example:

Input:

2
1 2 3 -1
4 5 6 7 -1

Output:

3 2 1 -1
7 6 5 4 -1

Constraints:

• 1 <= T <= 100
• 1 <= N <= 10^4
• 0 <= data <= 10^3