Rotate List: Given a list, rotate the list to the right by k places, where k is non-negative. (https://leetcode.com/problems/rotate-list/description/)

RotateListRight.java

/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode(int x) { val = x; }
 * }
 */
class RotateListRight {
    static int getLength(ListNode head) {
        int n = 0;
        for(ListNode help = head; help!=null; help = help.next, n++);
        return n;
    }
    
    static ListNode getLastNode(ListNode head){
        ListNode help;
        for(help = head; help.next != null; help = help.next);
        return help;
    }
    
    public ListNode rotateRight(ListNode head, int k) {
        int length = getLength(head);
        
        if(length == 0 || k%length == 0)
            return head;
        
        // 1. Point current last node to head node
        // 2. Find new last node
        // 3. Find new head node
        // 4. Make the new last node as the last node
        // 5. Make the new head node as the head node 
        
        ListNode lastNode = getLastNode(head);
        lastNode.next = head;
        
        int cutPoint = length - (k % length) - 1;
        ListNode help = head;
        for(int i = 0; i != cutPoint; i++){
            help = help.next;
        }
        ListNode newLastNode = help;
        ListNode newHead = help.next;
        
        newLastNode.next = null;
        head = newHead;
               
        return head;
    }
}