189. 旋转数组

public static void rotate(int[] nums, int k) {
        k = k%nums.length;
        reverse(nums,0,nums.length);
        reverse(nums,0,k);
        reverse(nums,k,nums.length);
    }
    public static void reverse(int[] nums,int start,int end) {
        int temp ;
        //交换
        while (start<end){
            temp=nums[end-1];
            nums[end-1]=nums[start];
            nums[start]=temp;
            start++;
            end--;
        }
    }