Rotate Matrix

Problem

Given a matrix representing a N x N 2D grid, rotate the matrix by 90 degrees in the clockwise direction. The rotation should be done in-place, which means modifying the input matrix directly without using an additional matrix for the rotation.

Examples

rotateMatrix([
  [1,2,3],
  [4,5,6],
  [7,8,9]
]);
/* returns [
  [7,4,1],
  [8,5,2],
  [9,6,3]
] 
Each value is rotated by 90 degrees clockwise */