07

2022/07/README.md

@@ -0,0 +1,11 @@
+# 07
+
+Loved this one too!! Writing a littler shell "emulator" was def. fun! Also caching directory sizes for performance :)
+
+<details>
+  <summary>Solutions</summary>
+  <ol>
+    <li>1306611</li>
+    <li>13210366</li>
+  </ol>
+</details>

2022/07/python/main.py

@@ -0,0 +1,115 @@
+#!/usr/bin/env python
+
+from dataclasses import dataclass
+from os.path import dirname, join
+from typing import Callable, ClassVar, Literal, Union
+
+# Day 07
+
+# Common
+
+
+def read_input(filename):
+    data = join(dirname(__file__), '..', filename)
+    with open(data) as f:
+        return f.read().strip()
+
+
+test = read_input('test.txt')
+data = read_input('input.txt')
+
+
+@dataclass
+class File:
+    size: int
+
+
+@dataclass
+class Directory:
+    name: str
+    contents: dict[str, Union['Directory', File]]
+    parent: Union[None, 'Directory'] = None
+    _size: int | None = None
+
+    def size(self) -> int:
+        if self._size is None:
+            self._size = sum([
+                entry.size if isinstance(entry, File) else entry.size()
+                for entry in self.contents.values()
+            ])
+        return self._size
+
+    def walk(self, fn: Callable[[Union[File, 'Directory']], None]):
+        for entry in self.contents.values():
+            fn(entry)
+            if isinstance(entry, Directory):
+                entry.walk(fn)
+
+
+@dataclass
+class Command:
+    command: str
+    output: list[str]
+
+
+@dataclass
+class Shell:
+    commands: list[Command]
+    root: Directory
+    cwd: Directory
+
+    def execute(self):
+        for command in self.commands:
+            cmd, *args = command.command.split()
+            match cmd:
+                case 'ls':
+                    for entry in command.output:
+                        size, name = entry.split()
+                        self.cwd.contents[name] = Directory(name, {}, self.cwd) if size == 'dir' else File(int(size))
+                case 'cd':
+                    match args[0]:
+                        case  '/':
+                            self.cwd = self.root
+                        case '..':
+                            self.cwd = self.cwd.parent
+                        case _:
+                            self.cwd = self.cwd.contents[args[0]]
+
+    def get_all_sizes(self) -> list[int]:
+        sizes: list[int] = []
+
+        def fn(entry: Directory | File):
+            if isinstance(entry, Directory):
+                sizes.append(entry.size())
+        self.root.walk(fn)
+        return sizes
+
+    def flag_1(self):
+        directories = self.get_all_sizes()
+        return sum([size for size in directories if size <= 100_000])
+
+    def flag_2(self, total=70_000_000, needed=30_000_000):
+        to_remove = needed - total + self.root.size()
+        big_enough = sorted([
+            size
+            for size in self.get_all_sizes()
+            if size > to_remove
+        ])
+        return big_enough[0]
+
+    @staticmethod
+    def parse(data: str):
+        commands = [command.strip().split('\n') for command in data.split('$ ')[1:]]
+        root = Directory('/', {})
+        return Shell([Command(command[0], command[1:]) for command in commands], root, root)
+
+
+shell = Shell.parse(test)
+shell.execute()
+print(shell.flag_1())
+print(shell.flag_2())
+
+shell = Shell.parse(data)
+shell.execute()
+print(shell.flag_1())
+print(shell.flag_2())