advent-of-code/2020/d02/ex2/ex2.py

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2020-12-02 11:20:32 +01:00
#!/usr/bin/env python
import re
import sys
from dataclasses import dataclass
from typing import List
@dataclass
class Policy:
min: int
max: int
letter: str
@dataclass
class Password:
policy: Policy
password: str
def is_valid(pwd: Password) -> bool:
min = pwd.password[pwd.policy.min - 1] == pwd.policy.letter
max = pwd.password[pwd.policy.max - 1] == pwd.policy.letter
return min ^ max
def solve(passwords: List[Password]) -> int:
return sum(map(is_valid, passwords))
def main() -> None:
pattern = re.compile("([0-9]+)-([0-9]+) (.): (.+)")
input = [
Password(Policy(int(m.group(1)), int(m.group(2)), m.group(3)), m.group(4))
for m in (pattern.match(line) for line in sys.stdin.readlines())
if m
]
print(solve(input))
if __name__ == "__main__":
main()