Given a singly linked list, the task is to rearrange it in a way that all odd position nodes are together and all even positions node are together.
Assume the first element to be at position 1 followed by second element at position 2 and so on.

Example 1:

Input:
LinkedList: 1->2->3->4
Output: 1 3 2 4 
Explanation: 
Odd elements are 1, 3 and even elements are 
2, 4. Hence, resultant linked list is 
1->3->2->4.

Example 2:

Input:
LinkedList: 1->2->3->4->5
Output: 1 3 5 2 4 
Explanation: 
Odd elements are 1, 3, 5 and even elements are
2, 4. Hence, resultant linked list is
​1->3->5->2->4.

Your Task:
The task is to complete the function rearrangeEvenOdd() which rearranges the nodes in the linked list as required and return the head of the linked list.

Expected Time Complexity: O(N).
Expected Auxiliary Space: O(1).

Constraints:
1 <= Size of the linked list <= 10000
1 <= values of linked list<= 1000