版权声明:本文为博主原创文章,未经博主允许不得转载。 https://blog.csdn.net/pku_langzi/article/details/85080325
原题链接:https://leetcode.com/problems/rotate-list/description/
Given a linked list, rotate the list to the right by k places, where k is non-negative.
Example 1:
Input: 1->2->3->4->5->NULL, k = 2
Output: 4->5->1->2->3->NULL
Explanation:
rotate 1 steps to the right: 5->1->2->3->4->NULL
rotate 2 steps to the right: 4->5->1->2->3->NULL
Example 2:
Input: 0->1->2->NULL, k = 4
Output: 2->0->1->NULL
Explanation:
rotate 1 steps to the right: 2->0->1->NULL
rotate 2 steps to the right: 1->2->0->NULL
rotate 3 steps to the right: 0->1->2->NULL
rotate 4 steps to the right: 2->0->1->NULL
#Definition for singly-linked list.
# class ListNode:
# def __init__(self, x):
# self.val = x
# self.next = None
class Solution:
def rotateRight(self, head, k):
"""
:type head: ListNode
:type k: int
:rtype: ListNode
"""
#首先过一遍链表,计算总共有多少个元素
current = head
size = 0
while current:
size += 1
tail = current
current = current.next
if size == 0:
return None
if k%size == 0:
return head
else:
index = head
for i in range (size-k%size-1):
index = index.next
last = index
new_head = last.next
tail.next = head
last.next = None
return new_head