hw 1 and 2

2024-1-12.py

@@ -0,0 +1,69 @@
+from util import *
+
+
+def p1():
+	# Language rule 1, n is less than or equal to 2
+	n = 2
+	# Language rule 2, m is less than or equal to n
+	m = n
+	strings = []
+	# Language rule 3, n and m are both non-negative integers
+	for i in range(0, n + 1):
+		for j in range(0, m + 1):
+			if j > i:
+				continue
+			strings.append('0' * j + '1' * i)
+
+	return strings
+
+
+def p2():
+	possible_n = [2, 3, 4, 5, 6]
+
+	strings = []
+	for i in possible_n:
+		integer_divisors = []
+		for j in range(1, i + 1):
+			if i % j == 0:
+				integer_divisors.append(j)
+		for j in integer_divisors:
+			strings.append('a' * j + 'b' * i)
+	return strings
+
+
+def p3():
+	possible_n = [1, 2, 3]
+
+	strings = []
+	for i in possible_n:
+		an = i
+		bn = 2 * i - 1
+		cn = 3 * i - 2
+		strings.append('a' * an + 'b' * bn + 'c' * cn)
+
+	return strings
+
+
+def p4():
+	alphabet = ['a', 'b']
+
+	# include empty string
+	strings = get_all_strings_with_a_given_alphabet_and_length(alphabet, 3)
+
+	def is_palindrome(s):
+		return s == s[::-1]
+
+	strings = list(filter(is_palindrome, strings))
+
+	return strings
+
+
+def main():
+	print_strings(p1())
+	print_strings(p2())
+	print_strings(p3())
+	print_strings(p4())
+
+
+if __name__ == '__main__':
+	main()

2024-1-15.py

@@ -0,0 +1,58 @@
+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 main():
+	print_strings(p1())
+	print_strings(p2())
+	print_strings(p3())
+
+
+if __name__ == '__main__':
+	main()

util.py

@@ -0,0 +1,13 @@
+def get_all_strings_with_a_given_alphabet_and_length(alphabet, length):
+	strings = ['']
+	for i in range(length):
+		s = [s + c for s in strings for c in alphabet]
+		strings += s
+
+	# Remove duplicates (set() isn't as nice as it doesn't preserve order, at least for verification purposes)
+	strings = list(dict.fromkeys(strings))
+	return strings
+
+
+def print_strings(strings):
+	print(strings, len(strings))