From 35fad0bd82c650a2939d9650e80797c9f9ffa973 Mon Sep 17 00:00:00 2001
From: Bruno BELANYI <bruno@belanyi.fr>
Date: Wed, 7 Dec 2022 09:18:34 +0100
Subject: [PATCH] 2022: d07: ex1: add solution

---
 2022/d07/ex1/ex1.py | 69 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 69 insertions(+)
 create mode 100755 2022/d07/ex1/ex1.py

diff --git a/2022/d07/ex1/ex1.py b/2022/d07/ex1/ex1.py
new file mode 100755
index 0000000..43e49f1
--- /dev/null
+++ b/2022/d07/ex1/ex1.py
@@ -0,0 +1,69 @@
+#!/usr/bin/env python
+
+import sys
+from typing import Union
+
+FileSystem = dict[str, Union[int, "FileSystem"]]
+
+
+def solve(input: list[str]) -> int:
+    def build_tree(input: list[str], i: int = 0) -> tuple[FileSystem, int]:
+
+        fs: FileSystem = {}
+
+        while i < len(input):
+            assert input[i][0] == "$"  # Sanity check
+            command = input[i].split()[1:]
+            if command[0] == "ls":
+                while (i := i + 1) < len(input):
+                    if input[i][0] == "$":
+                        break
+                    else:
+                        type, name = input[i].split()
+                        if type == "dir":
+                            continue
+                        fs[name] = int(type)
+            elif command[0] == "cd":
+                if command[1] == "..":
+                    i += 1
+                    break
+                else:
+                    fs[command[1]], i = build_tree(input, i + 1)
+            else:
+                assert False  # Sanity check
+
+        return fs, i
+
+    def total_size(
+        fs: FileSystem, parent_path: str = ""
+    ) -> dict[str, tuple[int, bool]]:
+        sizes: dict[str, tuple[int, bool]] = {}
+
+        for f, content in fs.items():
+            path = f"{parent_path}/{f}"
+            if isinstance(content, int):
+                sizes[path] = content, False
+            elif isinstance(content, dict):
+                children_sizes = total_size(content, path)
+                total = sum(children_sizes[f"{path}/{c}"][0] for c in content.keys())
+                sizes[path] = total, True
+                sizes.update(children_sizes)
+            else:
+                assert False  # Sanity check
+
+        return sizes
+
+    fs, i = build_tree(input)
+    assert i == len(input)  # Sanity check
+    sizes = total_size(fs)
+    THRESHOLD = 100000
+    return sum(size for size, is_dir in sizes.values() if is_dir and size <= THRESHOLD)
+
+
+def main() -> None:
+    input = sys.stdin.read().splitlines()
+    print(solve(input))
+
+
+if __name__ == "__main__":
+    main()