day07 finished

README.md

@@ -2,12 +2,13 @@
 
 Here are my solutions for [Advent of Code 2022](https://adventofcode.com/2022). Thanks to [Eric Wastl](http://was.tl) for the great puzzles and the great time I have solving them.
 
-My goal is to solve each puzzle on the day it was posted. Also I want to create code that is correct (of course), but some I would also understand in about a year. So a readable solution is preferable to one that is only correct. This is why I use TDD, classes and comments where they technically might not be necessary.
+My goal is to solve each puzzle on the day it was posted. Also I want to create code that is correct (of course), but which I still understand in about a year. So a readable solution is preferable to one that is only correct. This is why I use TDD, classes and comments where they technically might not be necessary. I often refine my solution after I handed it in.
 
 I use python 3.11 without any libraries beyond the standard.
 
 | Day | Time      | Rank  | Score | Time     | Rank  | Score |
 | --- | --------- | ----- | ----- | -------- | ----- | ----- |
+|  7  | 00:34:59  |  2683 |     0 | 00:45:45 |  2943 |     0 |
 |  6  | 00:14:52  |  9153 |     0 | 00:17:06 |  8413 |     0 |
 |  5  | 01:01:27  | 11570 |     0 | 01:05:20 | 10701 |     0 |
 |  4  | 00:12:09  |  5789 |     0 | 00:16:03 |  5187 |     0 |

advent/days/day07/data/test01.txt

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+$ cd /
+$ ls
+dir a
+14848514 b.txt
+8504156 c.dat
+dir d
+$ cd a
+$ ls
+dir e
+29116 f
+2557 g
+62596 h.lst
+$ cd e
+$ ls
+584 i
+$ cd ..
+$ cd ..
+$ cd d
+$ ls
+4060174 j
+8033020 d.log
+5626152 d.ext
+7214296 k

advent/days/day07/solution.py

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+from __future__ import annotations
+from dataclasses import dataclass, field
+
+from typing import Iterator
+
+day_num = 7
+
+
+def part1(lines: Iterator[str]) -> int:
+    return Directory.parse(lines).get_maxed_size(100_000)
+
+
+def part2(lines: Iterator[str]) -> int:
+    directory = Directory.parse(lines)
+    return directory.get_min_delete_size(70_000_000, 30_000_000)
+
+
+@dataclass(slots=True)
+class Directory:
+    name: str
+    parent: Directory | None
+    subdirs: list[Directory] = field(default_factory=list)
+    files: list[tuple[str, int]] = field(default_factory=list)
+    size: int | None = None
+
+    def cd_into(self, name: str) -> Directory:
+        """
+        Returns the named sub directory or .. for parent
+        May fail if unkown subdirectory - or already in root
+        """
+        if name == "..":
+            if self.parent is None:
+                raise Exception('Already at root Directory')
+            return self.parent
+
+        for sub in self.subdirs:
+            if sub.name == name:
+                return sub
+        raise Exception(f"Could not find subdir {name}")
+
+    def add_directory(self, name: str):
+        """ Adds the named directory."""
+        self.subdirs.append(Directory(name, self))
+
+    def add_file(self, name: str, size: int):
+        """ Adds the given file and size """
+        self.files.append((name, size))
+
+    def get_size(self) -> int:
+        """ returns the size of this directory including all subdirectories """
+        if self.size is None:
+            self.size = (sum(size for _, size in self.files)
+                         + sum(sub.get_size() for sub in self.subdirs))
+        return self.size
+
+    def get_all_directories(self) -> Iterator[Directory]:
+        """ Returns an iterator of all subdirectories """
+        for sub in self.subdirs:
+            yield from sub.get_all_directories()
+        yield self
+
+    def get_maxed_size(self, threshold: int) -> int:
+        """ Returns the sum of all sizes of subdirectories, that are below the given threshold"""
+        return sum(size for size in
+                   (dir.get_size() for dir in self.get_all_directories())
+                   if size <= threshold)
+
+    def get_min_delete_size(self, disk_size: int, space_needed: int) -> int:
+        """
+        Returns the size of the smallest directory that must be removed to created the free space
+        given as a parameter and the given disk size
+        #"""
+        unused = disk_size - self.get_size()
+        minimum: int | None = None
+        for dir in self.get_all_directories():
+            size = dir.get_size()
+            if unused + size >= space_needed and (minimum is None or minimum > size):
+                minimum = size
+
+        if minimum is None:
+            raise Exception("Could not find large enough directory to remove")
+
+        return minimum
+
+    @staticmethod
+    def parse(lines: Iterator[str]) -> Directory:
+        line = next(lines)
+        if line != '$ cd /':
+            raise Exception(f"Illegal first line: {line}")
+
+        root = Directory('/', None)
+        current = root
+        for line in lines:
+            match line.split():
+                case ['$', 'cd', name]:
+                    current = current.cd_into(name)
+
+                case ['$', 'ls']:
+                    pass
+
+                case ['dir', name]:
+                    current.add_directory(name)
+
+                case [size, name]:
+                    current.add_file(name, int(size))
+
+                case _:
+                    raise Exception(f"Could not parse line: {line}")
+
+        return root

advent/days/day07/test_solution.py

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+from advent.common import utils
+
+from .solution import day_num, part1, part2, Directory
+
+
+def test_part1():
+    data = utils.read_data(day_num, 'test01.txt')
+    expected = 95437
+    result = part1(data)
+    assert result == expected
+
+
+def test_part2():
+    data = utils.read_data(day_num, 'test01.txt')
+    expected = 24933642
+    result = part2(data)
+    assert result == expected
+
+
+def test_size():
+    data = utils.read_data(day_num, 'test01.txt')
+    expected = 48381165
+    directory = Directory.parse(data)
+    result = directory.get_size()
+    assert result == expected
+
+
+def test_maxed_size():
+    data = utils.read_data(day_num, 'test01.txt')
+    expected = 95437
+    directory = Directory.parse(data)
+    result = directory.get_maxed_size(100_000)
+    assert result == expected
+
+
+def test_find_to_delete():
+    data = utils.read_data(day_num, 'test01.txt')
+    expected = 24933642
+    directory = Directory.parse(data)
+    result = directory.get_min_delete_size(70_000_000, 30_000_000)
+    assert result == expected