[LeetCode]--189. Rotate Array

Rotate an array of n elements to the right by k steps.

For example, with n = 7 and k = 3, the array [1,2,3,4,5,6,7] is rotated to [5,6,7,1,2,3,4].

Note:
Try to come up as many solutions as you can, there are at least 3 different ways to solve this problem.

[show hint]

Hint:
Could you do it in-place with O(1) extra space?
Related problem: Reverse Words in a String II

Credits:
Special thanks to @Freezen for adding this problem and creating all test cases.

我想到的就是反转，但是开始写的反转用了惯性思维，用下标控制，很不理想，花费大量时间还弄不精确，后来看了个湄公河，嘿嘿，一下反应到用m，n分别是起始位置和结束位置，然后一直到m

public void rotate(