
# Lint as: python3
import itertools
import os
import re


lowerCamelCase__	=							re.compile(R"([A-Z]+)([A-Z][a-z])")
lowerCamelCase__	=							re.compile(R"([a-z\d])([A-Z])")

lowerCamelCase__	=							re.compile(R"(?<!_)_(?!_)")
lowerCamelCase__	=							re.compile(R"(_{2,})")

lowerCamelCase__	=							R"^\w+(\.\w+)*$"

lowerCamelCase__	=							R"<>:/\|?*"


def 							__A(lowerCAmelCase )		->				Any:

		"""simple docstring"""






		_UpperCamelCase						    =	_uppercase_uppercase_re.sub(R"""\1_\2"""						,  lowerCAmelCase )
		_UpperCamelCase						    =	_lowercase_uppercase_re.sub(R"""\1_\2"""						,  lowerCAmelCase )
		return name.lower()


def 							__A(lowerCAmelCase )		->				Tuple:

		"""simple docstring"""






		_UpperCamelCase						    =	_single_underscore_re.split(lowerCAmelCase )
		_UpperCamelCase						    =	[_multiple_underscores_re.split(lowerCAmelCase ) for n in name]
		return "".join(n.capitalize() for n in itertools.chain.from_iterable(lowerCAmelCase ) if n != """""" )


def 							__A(lowerCAmelCase )		->				Tuple:

		"""simple docstring"""






		if os.path.basename(lowerCAmelCase ) != name:
				raise ValueError(F'Should be a dataset name, not a path: {name}' )
		return camelcase_to_snakecase(lowerCAmelCase )


def 							__A(lowerCAmelCase						,  lowerCAmelCase )		->				List[str]:

		"""simple docstring"""






		if os.path.basename(lowerCAmelCase ) != name:
				raise ValueError(F'Should be a dataset name, not a path: {name}' )
		if not re.match(_split_re						,  lowerCAmelCase ):
				raise ValueError(F'Split name should match \'{_split_re}\'\' but got \'{split}\'.' )
		return F'{filename_prefix_for_name(lowerCAmelCase )}-{split}'


def 							__A(lowerCAmelCase						,  lowerCAmelCase						,  lowerCAmelCase						,  lowerCAmelCase=None )		->				List[str]:

		"""simple docstring"""






		_UpperCamelCase						    =	filename_prefix_for_split(lowerCAmelCase						,  lowerCAmelCase )
		if filetype_suffix:
				prefix += F'.{filetype_suffix}'
		_UpperCamelCase						    =	os.path.join(lowerCAmelCase						,  lowerCAmelCase )
		return F'{filepath}*'







def 							__A(lowerCAmelCase						,  lowerCAmelCase						,  lowerCAmelCase						,  lowerCAmelCase=None						,  lowerCAmelCase=None )		->				Optional[Any]:

		"""simple docstring"""






		_UpperCamelCase						    =	filename_prefix_for_split(lowerCAmelCase						,  lowerCAmelCase )
		_UpperCamelCase						    =	os.path.join(lowerCAmelCase						,  lowerCAmelCase )

		if shard_lengths:
				_UpperCamelCase						    =	len(lowerCAmelCase )
				_UpperCamelCase						    =	[F'{prefix}-{shard_id:05d}-of-{num_shards:05d}' for shard_id in range(lowerCAmelCase )]
				if filetype_suffix:
						_UpperCamelCase						    =	[filename + F'.{filetype_suffix}' for filename in filenames]
				return filenames
		else:
				_UpperCamelCase						    =	prefix
				if filetype_suffix:
						filename += F'.{filetype_suffix}'
				return [filename]





from __future__ import annotations


def 							__A(lowerCAmelCase						,  lowerCAmelCase						,  lowerCAmelCase						,  lowerCAmelCase						,  lowerCAmelCase						,  )		->				None:

		"""simple docstring"""






		_UpperCamelCase						    =	len(lowerCAmelCase )

		# 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(lowerCAmelCase ):
				# 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]						,  lowerCAmelCase						,  lowerCAmelCase						,  )


def 							__A(lowerCAmelCase )		->				None:

		"""simple docstring"""






		_UpperCamelCase						    =	[]
		depth_first_search([]						,  []						,  []						,  lowerCAmelCase						,  lowerCAmelCase )

		# Print all the boards
		for board in boards:
				for column in board:
						print(lowerCAmelCase )
				print("""""" )

		print(len(lowerCAmelCase )						,  """solutions were found.""" )


if __name__ == "__main__":
		import doctest

		doctest.testmod()
		n_queens_solution(4)



