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]

Related problem: Reverse Words in a String II

 1 class Solution {
 2     public void rotate(int[] nums, int k) {
 3         k%=nums.length;
 4         if(k==0) return;
 5         
 6     
 7         reverce(nums,0,nums.length-1);
 8         reverce(nums,0,k-1);
 9         reverce(nums,k,nums.length-1);
 
10     }
11     private void reverce(int[] a,int i,int j){
12         for(int k = 0;k <= (j-i)/2;k++){
13             swap(a,i+k,j-k);
14         }
15     }
16     private void swap(int[] a,int i ,int j){
17         int temp = a[i];
18         a[i] = a[j];
19         a[j] = temp;
20     }
21 }

189. Rotate Array(兩次反轉)