advent-of-code/2022/d07/ex1/ex1.py
Bruno BELANYI b4762ccf9f nix: migrate to 'ruff'
Having just the one tool is better.

Incidentally, this fixes the ternary formatting, which was messed up in
recent `black` versions.
2024-12-03 10:29:26 +00:00

69 lines
2 KiB
Python
Executable file

#!/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()