15. Matrix Rotation

Write a function solve that rotates an n x n matrix 90 degrees clockwise in-place.

Example:
Input: [
[1,2,3],
[4,5,6],
[7,8,9]]
Output: [
[7,4,1],
[8,5,2],
[9,6,3]]

Run this challenge interactively in Python or JavaScript when the app loads.