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12

Delete Alternate Nodes

Difficulty: EASY
Contributed By
Avg. time to solve
20 min
Success Rate
80%

Problem Statement

Given a Singly Linked List of integers, delete all the alternate nodes in the list.

Example:
List: 10 -> 20 -> 30 -> 40 -> 50 -> 60 -> null
Alternate nodes will be:  20, 40, and 60.

Hence after deleting, the list will be:
Output: 10 -> 30 -> 50 -> null
Note :
The head of the list will remain the same. Don't need to print or return anything.
Input format :
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 Format :
The only line of output will contain the updated list elements.
Input Constraints:
1 <= N <= 10 ^ 6.
Where N is the size of the Singly Linked List

Time Limit: 1 sec
Sample Input 1:
1 2 3 4 5 -1
Sample Output 1:
1 3 5
Explanation of Sample Input 1:
2, 4 are alternate nodes so we need to delete them 
Sample Input 2:
10 20 30 40 50 60 70 -1
Sample Output 2:
10 30 50 70 
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