advent-of-code/2022/day13_distress.py

96 lines
2.7 KiB
Python

from __future__ import annotations
import ast
from functools import cmp_to_key
def main(filename: str, expected_part_1: int = None, expected_part_2: int = None):
print(f"\n+ Running on {filename}")
with open(filename) as f:
data = f.read().strip().split("\n\n")
data = parse_data(data)
solution_part_1 = solve_part_1(data)
print(f"1. Found {solution_part_1}")
if expected_part_1:
assert expected_part_1 == solution_part_1
solution_part_2 = solve_part_2(data)
print(f"2. Found {solution_part_2}")
if expected_part_2:
assert expected_part_2 == solution_part_2
DataType = list[tuple[list, list]]
def parse_data(data: list[str]) -> DataType:
pairs = []
for pair in data:
left, right = pair.split("\n")
left = ast.literal_eval(left)
right = ast.literal_eval(right)
pairs.append((left, right))
return pairs
def solve_part_1(data: DataType) -> int:
total = 0
for index, pair in enumerate(data):
left, right = pair
if lower_than(left, right):
total += index + 1
return total
def lower_than(left: list, right: list) -> bool | None: # noqa: C901
"""True if left is lower than right."""
for left_item, right_item in zip(left, right):
if isinstance(left_item, int) and isinstance(right_item, int):
if left_item < right_item:
return True
elif left_item > right_item:
return False
elif isinstance(left_item, list) and isinstance(right_item, list):
if (res := lower_than(left_item, right_item)) is not None:
return res
elif isinstance(left_item, int):
if (res := lower_than([left_item], right_item)) is not None:
return res
elif isinstance(right_item, int):
if (res := lower_than(left_item, [right_item])) is not None:
return res
if len(left) == len(right):
return None
return len(left) < len(right)
def cmp(left: list, right: list) -> int:
if lower_than(left, right):
return -1
else:
return 1
def solve_part_2(data: DataType) -> int:
dividers = [[[2]], [[6]]]
packets = dividers[::]
for left, right in data:
packets.append(left)
packets.append(right)
packets.sort(key=cmp_to_key(cmp))
indices = []
for index, packet in enumerate(packets):
if packet in dividers:
indices.append(index + 1)
return indices[0] * indices[1]
if __name__ == "__main__":
main("inputs/day13-test1", expected_part_1=13, expected_part_2=140)
main("inputs/day13", expected_part_1=5503, expected_part_2=20952)