class Solution:
    def rotateRight(self, head: ListNode, k: int) -> ListNode:
        if not head:
            return
        thisNode = head
        n = 1
        while thisNode.next:
            n += 1
            thisNode = thisNode.next
        k = n - k % n
        thisNode.next = head
        n = 0
        while n < k:
            preNode = head
            head = head.next
            n += 1
        preNode.next = None
        return head

链表，中等

https://leetcode-cn.com/problems/rotate-list/