day 2

02/02.py

@@ -0,0 +1,35 @@
+def read_file():
+	with open("input.txt","r") as f:
+		return f.read().split('\n')
+
+def part1(passwords):
+	valid = 0
+	for entry in passwords:
+		[policy, password] = entry.split(': ')
+		[counts, character] = policy.split(' ')
+		[minimum, maximum] = counts.split('-')
+		if int(minimum) <= password.count(character) <= int(maximum):
+			valid += 1
+	return valid
+
+def part2(passwords):
+	valid = 0
+	for entry in passwords:
+		[policy, password] = entry.split(': ')
+		[positions, character] = policy.split(' ')
+		[p1, p2] = positions.split('-')
+		p1 = int(p1) - 1 # convert 1-index to 0-index
+		p2 = int(p2) - 1 # convert 1-index to 0-index
+		first_match = password[p1] == character
+		second_match = password[p2] == character
+		if first_match + second_match == 1: # exclusive or
+			valid += 1
+	return valid
+
+def main():
+	passwords = read_file()
+	print(f"Part 1: {part1(passwords)}")
+	print(f"Part 2: {part2(passwords)}")
+
+if __name__ == "__main__":
+	main()