Algorithm/90_degree at master · CodingProgrammer/Algorithm · GitHub

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#The matrix must be n*n
def RotatePrint(arr, top_x, top_y, down_x, down_y):
	i, step = 0, down_x - top_x
	while i < step:
		arr[top_x][top_y + i], arr[top_x + i][down_y] = arr[top_x + i][down_y], arr[top_x][top_y + i]
		arr[top_x][top_y + i], arr[down_x][down_y - i] = arr[down_x][down_y - i], arr[top_x][top_y + i]
		arr[top_x][top_y + i], arr[down_x - i][top_y] =  arr[down_x - i][top_y], arr[top_x][top_y + i]
		i += 1


l = [[1, 2 ,3], [4, 5, 6], [7, 8, 9]]
if len(l) % 2:
	layer = len(l) // 2 + 1
else:
	layer = len(l) // 2

top_x, top_y, down_x, down_y = 0, 0, len(l) -1, len(l)- 1
for i in range(layer):
	RotatePrint(l, top_x, top_y, down_x, down_y)
	top_x, top_y = top_x + 1, top_y + 1
	down_x, down_y = down_x - 1, down_y - 1

print(l)