from util import *


def p1():
	alphabet = ['a', 'b']

	strings = get_all_strings_with_a_given_alphabet_and_length(alphabet, 3)

	def number_of_a_is_even(s):
		return s.count('a') % 2 == 0

	strings = list(filter(number_of_a_is_even, strings))
	return strings


def p2():
	possible_m = [0, 1, 2, 3, 4]
	possible_n = [0, 1, 2, 3, 4]
	possible_p = [0, 1, 2, 3, 4]

	strings = []
	for m in possible_m:
		for n in possible_n:
			for p in possible_p:
				# First rule
				if m + n + p <= 4:
					# Second rule
					if m > n:
						# Third rule
						if n == p:
							strings.append('a' * m + 'b' * n + 'c' * p)
	return strings


def p3():
	alphabet = ['a', 'b', 'c']
	strings = get_all_strings_with_a_given_alphabet_and_length(alphabet, 4)

	def number_of_a_is_greater_than_number_of_b(s):
		return s.count('a') > s.count('b')

	def number_of_b_is_equal_to_number_of_c(s):
		return s.count('b') == s.count('c')

	strings = list(filter(number_of_a_is_greater_than_number_of_b, strings))
	strings = list(filter(number_of_b_is_equal_to_number_of_c, strings))

	return strings


def valid():
	alphabet = ['a', 'b']
	strings = get_all_strings_with_a_given_alphabet_and_length(alphabet, 5)

	def number_of_a_is_equal_to_3(s):
		return s.count('a') == 3

	def number_of_b_is_equal_to_3(s):
		return s.count('b') == 3

	# A game stops when a player has 3 a's or 3 b's, so there should be no trailing wins from the losing player
	def valid_game(s):
		if number_of_a_is_equal_to_3(s):
			return not s.endswith('b')
		elif number_of_b_is_equal_to_3(s):
			return not s.endswith('a')

	strings = list(filter(valid_game, strings))

	return strings


def p5():
	alphabet = ['a', 'b']
	valid_strings = valid()
	strings = get_all_strings_with_a_given_alphabet_and_length(alphabet, 5)

	def number_of_a_or_b_is_equal_to_3(s):
		return s.count('a') == 3 or s.count('b') == 3

	strings = list(filter(number_of_a_or_b_is_equal_to_3, strings))
	strings = [i for i in strings if i not in valid_strings]  # strings - valid_strings
	return strings


def p6():
	alphabet = ['a', 'b']
	valid_strings = valid()
	strings = get_all_strings_with_a_given_alphabet_and_length(alphabet, 5)

	def number_of_a_is_equal_to_3(s):
		return s.count('a') == 3

	def number_of_b_is_equal_to_3(s):
		return s.count('b') == 3

	def opposite_number_of_winner_is_less_than_3(s):
		if number_of_a_is_equal_to_3(s):
			return s.count('b') < 3
		elif number_of_b_is_equal_to_3(s):
			return s.count('a') < 3

	strings = list(filter(opposite_number_of_winner_is_less_than_3, strings))
	strings = [i for i in strings if i not in valid_strings]  # strings - valid_strings
	return strings


def main():
	print_strings(p1())
	print_strings(p2())
	print_strings(p3())
	print_strings(valid())
	print_strings(p5())
	print_strings(p6())


if __name__ == '__main__':
	main()