题出自https://leetcode.com/problems/rotate-image/ 内容为: You are given an n x n 2D matrix representing an image. Rotate the image by 90 degrees (clockwise). Follow up: Could you do this in-place? 简单的说就是给出一个n*n的二维数组,然后把这个数组进行90度顺时针旋转,而且不能使用额外的存储空间. 最初拿到这道题…