2 files changed, 112 insertions(+), 0 deletions(-)

A day07/day07.py
A day07/day07.test

@@ 0,0 1,89 @@
+#! /usr/bin/env python3
+# vim:fenc=utf-8
+#
+# Copyright © 2022 Adrian Perez de Castro <aperez@igalia.com>
+#
+# Distributed under terms of the MIT license.
+
+from dataclasses import dataclass, field
+from pathlib import PosixPath as Path
+
+@dataclass
+class Entry:
+    name: str
+
+@dataclass
+class File(Entry):
+    size: int
+
+@dataclass
+class Directory(Entry):
+    entries: list[Entry] = field(default_factory=list)
+
+    def walk(self, p: Path):
+        return self.__walk(p.parts)
+
+    def __walk(self, p: tuple[str]):
+        if len(p) == 0:
+            return self
+        elif p[0] == "/":
+            return top.__walk(p[1:])
+        else:
+            for item in self.entries:
+                if item.name == p[0]:
+                    if len(p) == 1:
+                        return item
+                    else:
+                        assert isinstance(item, Directory)
+                        return item.__walk(p[1:])
+            raise KeyError(p[0])
+
+    @property
+    def size(self):
+        return sum(item.size for item in self.entries)
+
+    def find(self, predicate):
+        if predicate(self):
+            yield self
+        for item in self.entries:
+            if isinstance(item, Directory):
+                yield from item.find(predicate)
+
+
+pwd = Path("/")
+top = Directory(name="/")
+cur = top
+
+import sys
+
+for line in sys.stdin.readlines():
+    items = line.strip().split()
+    assert len(items) >= 2
+    if items[0] == "$":
+        if items[1] == "cd":
+            assert len(items) == 3
+            if items[2] == "/":
+                pwd = Path("/")
+            elif items[2] == "..":
+                pwd = pwd.parent
+            else:
+                pwd = pwd / items[2]
+        elif items[1] == "ls":
+            assert len(items) == 2
+            cur = top.walk(pwd)
+        else:
+            assert False, "Unreachable"
+    else:
+        assert len(items) == 2
+        if items[0] == "dir":
+            cur.entries.append(Directory(items[1]))
+        else:
+            cur.entries.append(File(items[1], int(items[0])))
+
+if len(sys.argv) > 1:
+    for item in sys.argv[1:]:
+        print(top.walk(Path(item)).size)
+    raise SystemExit
+
+# Find all directories with a size at most 100000
+print(sum(item.size for item in top.find(lambda item: item.size <= 100000)))

@@ 0,0 1,23 @@
+$ 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