题目
Given a linked list, rotate the list to the right by k places, where k is non-negative.
解题思路
首先将将链表变成环，同时计算出一共有多少个结点，然后移动到(n-k%n-1)这个节点，其后一个节点为结果，并把这个节点的next指针变为空
代码
class Solution:
def rotateRight(self, head: ListNode, k: int) -> ListNode:
if not head or not head.next:
return head
tail = head
n = 1
while head.next :
head = head.next
n += 1
head.next = tail
head = head.next
for i in range(n - k % n - 1):
head = head.next
res = head.next
head.next = None
return res
