advent-of-code/2022-python/output/day_07.py

54 lines
1.4 KiB
Python

from collections import defaultdict
from output import ints
def solve(data):
fs = defaultdict(int)
pwd = []
for cmd in data.splitlines():
if cmd.startswith("$ ls") or cmd.startswith("dir "):
continue
if cmd.startswith("$ cd"):
d = cmd.split()[-1]
match d:
case "/":
pwd = []
case "..":
pwd.pop()
case _:
pwd.append(d)
continue
a = ""
w = sum(ints(cmd))
# in example input, all directories have distinct names.
#
# the puzzle input have repeated directory names, e.g. both
# /d/a and /c/b/a (a subfolder named "a") exists.
#
# Furthermore, puzzle input also has cases of /a/b/a,
# e.g. a recurring across directory path.
#
# Lost several hours due to this.
fs[a] += w
for p in pwd:
a += f"/{p}"
fs[a] += w
p1 = sum(i for i in fs.values() if i <= 100_000)
free = 70_000_000 - fs[""]
needed = 30_000_000 - free
p2 = min(i for i in fs.values() if i >= needed)
return p1, p2
if __name__ == "__main__":
with open("./input/07.txt", "r") as f:
inp = f.read().strip()
p1, p2 = solve(inp)
print(p1)
print(p2)
assert p1 == 1644735
assert p2 == 1300850