Rotate Image

You are given an n × n 2D matrix representing an image. Rotate the image by 90 degrees clockwise.

You must rotate in-place — do not allocate another 2D matrix.

Example 1:

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

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

Example 2:

Input:
[[5, 1, 9,11],
 [2, 4, 8,10],
 [13,3, 6, 7],
 [15,14,12,16]]

Output:
[[15,13,2,5],
 [14,3,4,1],
 [12,6,8,9],
 [16,7,10,11]]

Constraints:

• n == matrix.length == matrix[i].length
• 1 <= n <= 20
• -1000 <= matrix[i][j] <= 1000