(LeetCode)旋转数组

原体描写叙述例如以下：

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

我的解答例如以下：

public class Solution {
    public void rotate(int[] nums, int k) {
	if(nums==null||k==0)
	{
		return;
	}
	k = k%nums.length;
	reverse(nums,0,nums.length-1);
	reverse(nums,0,k-1);
	reverse(nums,k,nums.length-1);
}
public void reverse(int[] a ,int start, int end)
	{
		while(start<end)
		{
			int temp = a[start];
			a[start] = a[end];
			a[end] = temp;
			start++;
			end--;
		}
	}
}