Delete the Middle Node from a Singly Linked List

Given a singly linked list of integers, the task is to remove the middle node from this list.

Input:

The first line of input includes an integer 'T' which denotes the number of test cases. 
Each test case consists of a single line containing the linked list elements separated by spaces, ending with -1 (which is not part of the list).

Output:

For every test case, produce the updated linked list after removing the middle node, separated by spaces and terminating with -1.
Render the output for each test case on a distinct line.

Example:

Input:

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

Output:

1 3 4 1 2 6 -1
1 2 4 -1

Constraints:

• 1 <= T <= 100
• 0 <= L <= 5000
• 1 <= data <= 10⁹ and data ≠ -1

Notes:

1. Return an empty list (i.e., NULL) if no middle node to delete exists.

2. If there are two middle nodes, remove the first one.

Follow-up: Can you achieve the solution in O(N) time and O(1) space complexity with just a single traversal of the list?