advent_of_code_2020/day2/day2.py

52 lines
1.5 KiB
Python
Executable file

#! /usr/bin/env python3
import pathlib
import sys
import re
from dataclasses import dataclass
@dataclass
class PasswordSpec:
first:int
second:int
letter:str
password:str
def parse(puzzle_input: str):
"""Parse input"""
regex = re.compile(r'^(\d+)-(\d+) (\w): (\w+)$')
toInt = lambda x: PasswordSpec(int(x[0]), int(x[1]), x[2], x[3])
return [toInt(regex.match(i).groups()) for i in puzzle_input.splitlines()]
def part1(data):
"""Solve part 1"""
test = lambda x: x.first<=x.password.count(x.letter)<=x.second
# these two lines are equivilant.
# return sum(1 for p in data if test(p))
return len([1 for p in data if test(p)])
def test_password(passwordSpec: PasswordSpec):
if passwordSpec.password[passwordSpec.first-1]==passwordSpec.letter:
return passwordSpec.password[passwordSpec.second-1]!=passwordSpec.letter
else:
return passwordSpec.password[passwordSpec.second-1]==passwordSpec.letter
def part2(data):
"""Solve part 2"""
return sum(1 for p in data if test_password(p))
def solve(puzzle_input):
"""Solve the puzzle for the given input"""
data = parse(puzzle_input)
solution1 = part1(data)
solution2 = part2(data)
return solution1, solution2
if __name__ == "__main__":
for path in sys.argv[1:]:
print(f"{path}:")
puzzle_input = pathlib.Path(path).read_text().strip()
solutions = solve(puzzle_input)
print("\n".join(str(solution) for solution in solutions))