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].
翻转三次就好了 第一次0----len-1，第二次0-----k-1，第三次k---len-1，
主要注意交换函数不要写错就好了。
交换的次数是N/2;
可以采用双指针法
class Solution {
public void rotate(int[] nums, int k) {
k = k%nums.length;
// in case overflow
rotate_0_n(nums,0,nums.length-1);
rotate_0_n(nums,0,k-1);
rotate_0_n(nums,k,nums.length-1);
}
private void rotate_0_n (int[] nums,int start,int end)
{
while(start<=end)
{
int temp = nums[start];
nums[start]=nums[end];
nums[end]=temp;
start++;
end--;
}
}
}
