You are given an n x n 2D matrix representing an image.
Rotate the image by 90 degrees (clockwise).
Follow up:
You are given an n x n 2D matrix representing an image.
Rotate the image by 90 degrees (clockwise).
Follow up:
翻轉一棵二叉樹。 示例: 輸入: 4 / \ 2 7 / \ / \ 1 3 6 9 輸出: 4 / \ 7 2 / \ / \ 9 6