





import os
import sys
from contextlib import contextmanager


# Windows only
if os.name == "nt":
							import ctypes
							import msvcrt  # noqa





							class 				a			(      ctypes.Structure			):
											# _fields is a specific attr expected by ctypes
											SCREAMING_SNAKE_CASE__     :   List[Any]		      =     [('''size''', ctypes.c_int), ('''visible''', ctypes.c_byte)]






def 		lowerCAmelCase  (	)      ->    Optional[int]:

						"""simple docstring"""





						if os.name == "nt":
												__SCREAMING_SNAKE_CASE:				Optional[int]           =   CursorInfo()
												__SCREAMING_SNAKE_CASE:				Union[str, Any]           =   ctypes.windll.kernelaa.GetStdHandle(-11					)
												ctypes.windll.kernelaa.GetConsoleCursorInfo(UpperCamelCase__       ,			ctypes.byref(UpperCamelCase__					)					)
												__SCREAMING_SNAKE_CASE:				Any           =   False
												ctypes.windll.kernelaa.SetConsoleCursorInfo(UpperCamelCase__       ,			ctypes.byref(UpperCamelCase__					)					)
						elif os.name == "posix":
												sys.stdout.write('''\033[?25l'''					)
												sys.stdout.flush()






def 		lowerCAmelCase  (	)      ->    Optional[int]:

						"""simple docstring"""





						if os.name == "nt":
												__SCREAMING_SNAKE_CASE:				Optional[Any]           =   CursorInfo()
												__SCREAMING_SNAKE_CASE:				List[str]           =   ctypes.windll.kernelaa.GetStdHandle(-11					)
												ctypes.windll.kernelaa.GetConsoleCursorInfo(UpperCamelCase__       ,			ctypes.byref(UpperCamelCase__					)					)
												__SCREAMING_SNAKE_CASE:				Optional[int]           =   True
												ctypes.windll.kernelaa.SetConsoleCursorInfo(UpperCamelCase__       ,			ctypes.byref(UpperCamelCase__					)					)
						elif os.name == "posix":
												sys.stdout.write('''\033[?25h'''					)
												sys.stdout.flush()






@contextmanager
def 		lowerCAmelCase  (	)      ->    List[str]:

						"""simple docstring"""





						try:
												hide_cursor()
												yield
						finally:
												show_cursor()










from __future__ import annotations






def 		lowerCAmelCase  (	UpperCamelCase__   :   list[int]       ,			UpperCamelCase__   :   list[int]       ,			UpperCamelCase__   :   list[int]       ,			UpperCamelCase__   :   list[list[str]]       ,			UpperCamelCase__   :   int       ,			)      ->    None:

						"""simple docstring"""





						__SCREAMING_SNAKE_CASE:				Any           =   len(UpperCamelCase__					)

						# If row is equal to the size of the board it means there are a queen in each row in
						# the current board (possible_board)
						if row == n:
												# We convert the variable possible_board that looks like this: [1, 3, 0, 2] to
												# this: ['. Q . . ', '. . . Q ', 'Q . . . ', '. . Q . ']
												boards.append(['''. ''' * i + '''Q ''' + '''. ''' * (n - 1 - i) for i in possible_board]					)
												return

						# We iterate each column in the row to find all possible results in each row
						for col in range(UpperCamelCase__					):
												# We apply that we learned previously. First we check that in the current board
												# (possible_board) there are not other same value because if there is it means
												# that there are a collision in vertical. Then we apply the two formulas we
												# learned before:
												#
												# 45º: y - x = b or 45: row - col = b
												# 135º: y + x = b or row + col = b.
												#
												# And we verify if the results of this two formulas not exist in their variables
												# respectively.  (diagonal_right_collisions, diagonal_left_collisions)
												#
												# If any or these are True it means there is a collision so we continue to the
												# next value in the for loop.
												if (
												    col in possible_board
												    or row - col in diagonal_right_collisions
												    or row + col in diagonal_left_collisions
												):
																		continue

												# If it is False we call dfs function again and we update the inputs
												depth_first_search(
												    [*possible_board, col]       ,			[*diagonal_right_collisions, row - col]       ,			[*diagonal_left_collisions, row + col]       ,			UpperCamelCase__       ,			UpperCamelCase__       ,			)






def 		lowerCAmelCase  (	UpperCamelCase__   :   int					)      ->    None:

						"""simple docstring"""





						__SCREAMING_SNAKE_CASE:				list[list[str]]           =   []
						depth_first_search([]       ,			[]       ,			[]       ,			UpperCamelCase__       ,			UpperCamelCase__					)

						# Print all the boards
						for board in boards:
												for column in board:
																		print(UpperCamelCase__					)
												print(''''''					)

						print(len(UpperCamelCase__					)       ,			'''solutions were found.'''					)


if __name__ == "__main__":
							import doctest

							doctest.testmod()
							n_queens_solution(4)



