Question

Write the program code to count the no of odd numbers present in a singly linked list (function only) ​

Answer 1

Answer:

Given a Linked List of integers, write a function to modify the linked list such that all even numbers appear before all the odd numbers in the modified linked list. Also, keep the order of even and odd numbers same.

Explanation:

17->15->8->12->10->5->4->1->7->6->NULL

Output: 8->12->10->4->6->17->15->5->1->7->NULL

Input: 8->12->10->5->4->1->6->NULL

Output: 8->12->10->4->6->5->1->NULL

// If all numbers are even then do not change the list

Input: 8->12->10->NULL

Output: 8->12->10->NULL

// If all numbers are odd then do not change the list

Input: 1->3->5->7->NULL

Output: 1->3->5->7->NULL

Recommended: Please solve it on “PRACTICE” first, before moving on to the solution.

Method 1

The idea is to get pointer to the last node of list. And then traverse the list starting from the head node and move the odd valued nodes from their current position to end of the list.

Thanks to blunderboy for suggesting this method.

Algorithm:

…1) Get pointer to the last node.

…2) Move all the odd nodes to the end.

……..a) Consider all odd nodes before the first even node and move them to end.

……..b) Change the head pointer to point to the first even node.

……..b) Consider all odd nodes after the first even node and move them to the end.