A first attempt at AOC 2021 Day 24

ALU.py

# requires Python@3.10

from dataclasses import dataclass, field
from operator import add, floordiv, mod, mul
from typing import Dict, Generator, List

@dataclass
class ALU:
    instructions: List[str] = field(repr=False)
    inputs: str = field(repr=False)
    memory: Dict[str, int] = field(
        default_factory=lambda: {"w": 0, "x": 0, "y": 0, "z": 0}
    )

    OPERATIONS = {"add": add, "mul": mul, "div": floordiv, "mod": mod}

    def value_of(self, val: str) -> int:
        if val in {"w", "x", "y", "z"}:
            return self.memory[val]
        return int(val)

    def run(self):
        inputs = self.get_inputs()
        for ins in self.instructions:
            match ins.split():
                case ["inp", var]:
                    self.memory[var] = next(inputs)
                case ["add" | "mul" | "div" | "mod" as op, var, val]:
                    self.memory[var] = self.OPERATIONS[op](
                        self.value_of(var), self.value_of(val)
                    )
                case ["eql", var, val]:
                    self.memory[var] = (
                        1 if self.value_of(var) == self.value_of(val) else 0
                    )
                case _:
                    raise NotImplementedError(f"unknown operation: {ins}")

    def get_inputs(self) -> Generator[int, None, None]:
        for i in self.inputs:
            yield int(i)

    @property
    def input_was_valid(self) -> bool:
        return self.memory["z"] == 0
      
class Solution(...):
    def part_1(self) -> int:
        i = int("9" * 14)
        while True:
            i -= 1

            model_number = str(i)
            if i % 10000 == 0:
                print(i)

            if "0" in model_number:
                continue

            alu = ALU(self.input, model_number)
            alu.run()
            if alu.input_was_valid:
                return i