描述：
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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
思路：
当然，一个很简单且容易想到的思路就是直接循环移位k位即可，但每次都要移动n个元素，即总共需要移动k*n个元素
和Reverse Words in a String II题目类似，还有一种通过改变固定数目的元素就可以实现移位数组的功能，即先将1~len-k，len-k~len之间的元素逆置，最后将1~len之间的元素逆置，可以实现最后的旋转数组的目的。
代码：
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public void rotate(int[] nums, int k) {
if(nums==null)
return;
int len=nums.length;
k=k%len;
if(k==0)
return;
int mid=len-k;
int temp=0;
int index=mid/2;
for(int i=0;i
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