题目套路
对指定的类型（数组，单链表，字符串）以指定规则进行扭转。
题目列表和思路：
189. Rotate Array
https://leetcode.com/problems/rotate-array
数组n，扭转次数k,现根据k和n取真实的扭转轴pivot。
然后将整个数组逆转，然后在轴的两边分别扭转。
举例：
nums=[1,2,3,4,5,6,7],k=2,n=7,move=k%n=2
[1,2,3,4,5,6,7]->[7,6,5,4,3,2,1]->[6,7,1,2,3,4,5]
61. Rotate List
https://leetcode.com/problems/rotate-list
思路与上题类似，先使用一个指针fast，计算出链表的长度。
151. Reverse Words in a String
https://leetcode.com/problems/reverse-words-in-a-string
186. Reverse Words in a String II
https://leetcode.com/problems/reverse-words-in-a-string-ii
思路为将整个字符串逆转，然后按照每个单词再逆转
"the sky is blue"->"eulb si yks eht"->"blue is sky the"
要注意，去除多余的空格
153. Find Minimum in Rotated Sorted Array
https://leetcode.com/problems/find-minimum-in-rotated-sorted-array
154. Find Minimum in Rotated Sorted Array II
https://leetcode.com/problems/find-minimum-in-rotated-sorted-array-ii
33. Search in Rotated Sorted Array
https://leetcode.com/problems/search-in-rotated-sorted-array
81. Search in Rotated Sorted Array II
https://leetcode.com/problems/search-in-rotated-sorted-array-ii
在已经被扭转的数组中进行搜索。
思路：先用二分查找找到扭转周pivot，然后再根据pivot的位置计算真实的mid，继续通过二分查找查找需要的元素。
CheckPoint1:怎么找扭转轴
CheckPoint2:找到扭转轴后如何利用真实的mid二分查找