# Definition for singly-linked list.
# class ListNode(object):
# def __init__(self, x):
# self.val = x
# self.next = None
class Solution(object):
def rotateRight(self, head, k):
"""
:type head: ListNode
:type k: int
:rtype: ListNode
"""
if not head or not head.next or k==0:
return head
n=self.getSize(head)
k%=n
dummy=ListNode(0)
dummy.next=head
p=head
for i in range(k):
p=p.next
for j in range(n-k-1):
p=p.next
head=head.next
p.next=dummy.next
dummy.next=head.next
head.next=None
return dummy.next
def getSize(self,head):
n=0
while head:
head=head.next
n+=1
return n
https://www.youtube.com/watch?v=7OBo9fBp1FE
