Matrix Rotation Challenge

matrix_rotation.py

# Given an image represented by an NxN matrix, where each pixel in the image is
# 4 bytes, write a method to rotate the image by 90 degrees. Can you do this in
# place?

# Displays the given matrix.
def display(matrix):
	N = len(matrix)

	for column in range(0, N):
		for row in range(0, N):
			print(f'{matrix[column][row]:02d} ', end='')
		print()

# Rotates the given NxN matrix by 90 degrees.
def rotate(matrix):
	# First, create N.
	N = len(matrix)

	# Second, calculate the number of rings needed.
	#
	# If N is odd, then the center element does not
	# need to rotate. Otherwise, it needs to rotate.
	# That is why a floor division is used.
	num_rings = N // 2

	# Next, loop through each ring and rotate them.
	for ring in range(0, num_rings):
		# First, calculate the maximum offset of a
		# ring.
		max_offset = N - (ring * 2) - 1

		# Next, loop through each offset and rotate
		# the 4 elements.
		for offset in range(0, max_offset):
			# First, the top left element should be
			# stored.
			origin = matrix[ring][ring+offset]

			# Next, move the bottom left element to
			# the top left.
			matrix[ring][ring+offset] = matrix[ring+max_offset-offset][ring]

			# Next, move the bottom right element to
			# the bottom left.
			matrix[ring+max_offset-offset][ring] = matrix[ring+max_offset][ring+max_offset-offset]

			# Next, move the top right element to
			# the bottom right.
			matrix[ring+max_offset][ring+max_offset-offset] = matrix[ring+offset][ring+max_offset]

			# Finally, set the top right element to
			# the origin.
			matrix[ring+offset][ring+max_offset] = origin
	
	# Finally, return the matrix
	return matrix

matrices = [
	[
		[1, 2, 3],
		[4, 5, 6],
		[7, 8, 9]
	],
	[
		[1,  2,  3,  4 ],
		[5,  6,  7,  8 ],
		[9,  10, 11, 12],
		[13, 14, 15, 16]
	],
	[
		[1,  2,  3,  4,  5 ],
		[6,  7,  8,  9,  10],
		[11, 12, 13, 14, 15],
		[16, 17, 18, 19, 20],
		[21, 22, 23, 24, 25],
	]
]

for matrix in matrices:
	print('000 DEGREES')
	display(matrix)
	print('090 DEGREES')
	display(rotate(matrix))
	print('180 DEGREES')
	display(rotate(matrix))
	print('270 DEGREES')
	display(rotate(matrix))
	print('-----------')