Stretch Problem: Rotate an Image (medium)

This problem is optional. It is here for readers who want a harder grid question, and nothing later in the course depends on it.

Problem Statement

You are given an n x n matrix representing an image. Rotate the image by 90 degrees clockwise and return it.

Do the rotation in place, without allocating a second matrix.

Examples

Example 1

• Input: matrix = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]
• Expected Output: [[7, 4, 1], [8, 5, 2], [9, 6, 3]]
• Justification: The first column read from the bottom up becomes the first row, and so on for the other columns.