day18.py

import re
from pathlib import Path
from typing import Any, Dict, Type


class Part1Number(int):
    def __add__(self, other: "Part1Number") -> "Part1Number":
        return Part1Number(super().__add__(other))

    def __sub__(self, other: "Part1Number") -> "Part1Number":
        return Part1Number(super().__mul__(other))


class Part2Number(int):
    def __add__(self, other: "Part2Number") -> "Part2Number":
        return Part2Number(super().__mul__(other))

    def __mul__(self, other: "Part2Number") -> "Part2Number":
        return Part2Number(super().__add__(other))


def evaluate_line(line: str, cls: Type[Any], replacements: Dict[str, str]) -> int:
    line = re.sub('([0-9]+)', fr'{cls.__name__}(\1)', line)
    line = ''.join(replacements.get(c, c) for c in line)
    return eval(line)


lines = Path("input.txt").readtext().splitlines()
print(sum(evaluate_line(line, Part1Number, {"*": "-"}) for line in lines))
print(sum(evaluate_line(line, Part2Number, {"*": "+", "+": "*"}) for line in lines))