rotateListJava

/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode() {}
 *     ListNode(int val) { this.val = val; }
 *     ListNode(int val, ListNode next) { this.val = val; this.next = next; }
 * }
 */
class Solution {
    public ListNode rotateRight(ListNode head, int k) {
        // edge cases 
        if (head == null || head.next == null|| k == 0) return head;
        
        // compute the length
        ListNode cur = head;
        int len = 1;
        while (cur.next != null) {
            len++; 
            cur = cur.next;
        } 
            
        
        // go till that node
        cur.next = head;
        k = k % len;
        k = len - k;
        while (k-- > 0) cur = cur.next;
        
        // make the node head and break connection 
        head = cur.next;
        cur.next = null;
        
        
        return head; 
    }
}