289.旋转数组

示例 1:

输入: nums = [1,2,3,4,5,6,7], k = 3
输出: [5,6,7,1,2,3,4]
解释:
向右旋转 1 步: [7,1,2,3,4,5,6]
向右旋转 2 步: [6,7,1,2,3,4,5]
向右旋转 3 步: [5,6,7,1,2,3,4]

public void rotate(Integer[] nums, int k) {
        if (k%nums.length==0) return;
        k%=nums.length;
        int length = nums.length;
        reverse(nums,0,length-1);
        reverse(nums,0,k-1);
        reverse(nums,k, length -1);
    }

    public void reverse(Integer[] arr,int start,int end){
        if (start==end) return;
        int temp;
        while (start<end){
            temp=arr[end];
            arr[end]=arr[start];
            arr[start]=temp;
            start++;
            end--;
        }
    }