Advent of Code 2022 - Day 7 - Python

from __future__ import annotations
from collections import deque
from typing import Optional


class Directory:
    def __init__(self, name: str, size: int = 0, parent: Optional[Directory]=None):
        self.name = name
        self.size = size
        self.parent = parent
        self.children: dict[str, Directory] = {}

    def __hash__(self):
        return hash(self.name)

    def __repr__(self):
        return f"{self.__class__.__name__}(\"{self.name}\", {self.size})"


def part_a(filepath):
    max_dir_size = 100000
    total = 0
    current = Directory("root")
    current.children["/"] = Directory("/")
    with open(filepath, "r") as f:
        for line in f.readlines():
            match line.strip().split():
                case["$", "ls"]:
                    continue
                case["$", "cd", ".."]:
                    if current.size <= max_dir_size:
                        total += current.size
                    current.parent.size += current.size
                    current = current.parent
                case ["$", "cd", name]:
                    current = current.children[name]
                case ["dir", directory_name]:
                    current.children[directory_name] = Directory(directory_name, parent=current)
                case [size, _]:
                    current.size += int(size)
    return total


def part_b(filepath):
    total_filesystem = 70_000_000
    needed_space = 30_000_000
    current_to_delete = 700_000_000
    current = Directory("root")
    current.children["/"] = Directory("/")
    with open(filepath, "r") as f:
        for line in f.readlines():
            match line.strip().split():
                case ["$", "ls"]:
                    continue
                case ["$", "cd", ".."]:
                    current.parent.size += current.size
                    current = current.parent
                case ["$", "cd", name]:
                    current = current.children[name]
                case ["dir", directory_name]:
                    current.children[directory_name] = Directory(directory_name, parent=current)
                case [size, _]:
                    current.size += int(size)
    while current.parent is not None:
        current.parent.size += current.size
        current = current.parent
    available = total_filesystem - current.size

    queue = deque()
    queue.append(current)

    while queue:
        directory = queue.popleft()
        if ((directory.size + available) >= needed_space) and (directory.size < current_to_delete):
            current_to_delete = directory.size
        for child in directory.children.values():
            queue.append(child)

    return current_to_delete


if __name__ == '__main__':
    print("Example 1")
    print(part_a(r"\data\day07_example.txt") == 95437)
    print(part_a(r"\data\day07.txt"))
    print(part_b(r"\data\day07_example.txt") == 24933642)
    print(part_b(r"\data\day07.txt"))