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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
``````
Console