DOCUMENTATION
Question link : https://www.interviewbit.com/problems/rotate-matrix/
Asked in : Google , Facebook, Amazon
You are given an n x n 2D matrix representing an image.
Rotate the image by 90 degrees (clockwise).
Example: If the array is
[
    [1, 2],
    [3, 4]
]    Then the rotated array becomes:
[
    [3, 1],
    [4, 2]
]
Approach - As we have to rotate the matrix image by 90. We can change the traversal of the matrix . If we print the column first from downward to upward direction then  then the rotated array will be printed .
Time and Space Complexity : 
Time - O(n^2)
Space - O(n)
Pseudocode :
for(j=0 to n)
	for(i=n-1 to 0)
		print(a[i][j])


