Delete Alternate Nodes from a Singly Linked List

Given a Singly Linked List of integers, remove all the alternate nodes from the list.

Input:

The first and the only line of input will contain the elements of the Singly Linked List separated by a single space and terminated by -1.

Output:

The only line of output will contain the updated list elements.

Example:

Input: 10 20 30 40 50 60 -1
Output: 10 30 50

Constraints:

• 1 <= N <= 10^6 where N is the size of the Singly Linked List.
• Time Limit: 1 sec

Note:

The head of the list will remain the same. You don't need to print or return anything from your function.