# leetle

## 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]]`

Make sure you `return` your solution, don't print!

```python

def solve(matrix):
    pass
```