Leetcode61. rotating linked list

Title transmission address : https://leetcode.cn/problems/rotate-list/

Operational efficiency ：

The code is as follows ：

 public static ListNode rotateRight(ListNode head, int k) {
    
        // Dealing with border situations 
        if(head==null||head.next==null||k==0){
    
            return  head;
        }
        // First, you need to know the length of the linked list 
        int length = 1;
        ListNode tailNode = head;  // Caudal node 
        // The traversal process also finds the tail node 
        while (tailNode.next != null) {
    
            length++;
            tailNode = tailNode.next;
        }
        // For example, the length of the linked list is 6, When k=11 and k=5 The effect of rotation is the same 
        k = k % length;
        if(k==0){
    
            return head;
        }
        // The position of the head node of the new linked list in the original linked list is length-k  The position of the tail node of the new linked list in the original linked list is length-k
        ListNode newTailNode = head;
        int index = 0;
        while (index < length - k-1) {
    
            newTailNode = newTailNode.next;
            index++;
        }
        ListNode newHeadNode = newTailNode.next;
        newTailNode.next = null;
        tailNode.next = head;
        return newHeadNode;
    }