Write a method firstLast that could be added to the LinkedIntList class that moves the first element of the list to the back end of the list. Suppose a LinkedIntList variable named list stores the following elements from front (left) to back (right):

[18, 4, 27, 9, 54, 5, 63] 

If you made the call of list.firstLast();, the list would then store the elements in this order:

[4, 27, 9, 54, 5, 63, 18] 

If the list is empty or has just one element, its contents should not be modified.

Obey the following restrictions in your solution:

• Do not call any other methods on the LinkedIntList object, such as add, remove, or size.
• Do not create new ListNode objects (though you may have as many ListNode variables as you like).
• Do not use other data structures such as arrays, lists, queues, etc.
• Do not mutate the data of any existing node; change the list only by modifying links between nodes.
• Your solution should run in O(N) time, where N is the number of elements of the linked list.

Assume that you are adding this method to the LinkedIntList class (that uses the ListNode class) below.

public class LinkedIntList { public class ListNode {

 private ListNode front; public int data;

 ... public ListNode next;

} ...

 }