RotateLinkedList.java

import java.util.*;

class ListNode {
    int value = 0;
    ListNode next;

    ListNode(int value) {
        this.value = value;
    }
}

class RotateLinkedList {

    public static ListNode rotate(ListNode head, int rotations) {
        if (head == null || head.next == null || rotations <= 0)
            return head;

        // find the length and the last node of the list
        ListNode lastNode = head;
        int listLength = 1;
        while (lastNode.next != null) {
            lastNode = lastNode.next;
            listLength++;
        }

        lastNode.next = head; // connect the last node with the head to make it a circular list
        rotations %= listLength; // no need to do rotations more than the length of the list
        int skipLength = listLength - rotations;
        ListNode lastNodeOfRotatedList = head;
        for (int i = 0; i < skipLength - 1; i++)
            lastNodeOfRotatedList = lastNodeOfRotatedList.next;

        // 'lastNodeOfRotatedList.next' is pointing to the sub-list of 'k' ending nodes
        head = lastNodeOfRotatedList.next;
        lastNodeOfRotatedList.next = null;
        return head;
    }

    public static void main(String[] args) {
        ListNode head = new ListNode(1);
        head.next = new ListNode(2);
        head.next.next = new ListNode(3);
        head.next.next.next = new ListNode(4);
        head.next.next.next.next = new ListNode(5);
        head.next.next.next.next.next = new ListNode(6);

        ListNode result = RotateLinkedList.rotate(head, 3);
        System.out.print("Nodes of the reversed LinkedList are: ");
        while (result != null) {
            System.out.print(result.value + " ");
            result = result.next;
        }
    }
}