aoc/02/02.py

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('-')
		minimum = int(minimum)
		maximum = int(maximum)
		if minimum <= password.count(character) <= 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()