40 lines
1.6 KiB
Python
40 lines
1.6 KiB
Python
|
# SPDX-License-Identifier: MIT
|
||
|
|
# Copyright (c) 2021 Akumatic
|
||
|
|
#
|
||
|
|
# https://adventofcode.com/2021/day/20
|
||
|
|
|
||
|
|
def read_file(filename: str = "input.txt") -> tuple:
|
||
|
|
with open(f"{__file__.rstrip('code.py')}{filename}", "r") as f:
|
||
|
|
lines = [line for line in f.read().strip().split("\n")]
|
||
|
|
algorithm = list(lines[0])
|
||
|
|
image = {(x,y - 2):lines[y][x] for x in range(len(lines[2])) for y in range(2, len(lines))}
|
||
|
|
return image, algorithm
|
||
|
|
|
||
|
|
def step(image: dict, algorithm: list, default: str) -> dict:
|
||
|
|
min_point = min(image.keys())
|
||
|
|
max_point = max(image.keys())
|
||
|
|
new_image = dict()
|
||
|
|
for y in range(min_point[1] - 1, max_point[1] + 2):
|
||
|
|
for x in range(min_point[0] - 1, max_point[0] + 2):
|
||
|
|
tmp = [image.get((i, j), default) for j in (y-1, y, y+1) for i in (x-1, x, x+1)]
|
||
|
|
idx = int("".join(["0" if i == "." else "1" for i in tmp]), 2)
|
||
|
|
new_image[(x, y)] = algorithm[idx]
|
||
|
|
return new_image
|
||
|
|
|
||
|
|
def get_light_pixels_after_iterations(image: dict, algorithm: list, iterations: int) -> int:
|
||
|
|
for i in range(iterations):
|
||
|
|
default = "." if algorithm[0] == "." or i % 2 == 0 else "#"
|
||
|
|
image = step(image, algorithm, default)
|
||
|
|
return list(image.values()).count("#")
|
||
|
|
|
||
|
|
def part1(image: dict, algorithm: list) -> int:
|
||
|
|
return get_light_pixels_after_iterations(image, algorithm, 2)
|
||
|
|
|
||
|
|
def part2(image: dict, algorithm: list) -> int:
|
||
|
|
return get_light_pixels_after_iterations(image, algorithm, 50)
|
||
|
|
|
||
|
|
if __name__ == "__main__":
|
||
|
|
vals = read_file()
|
||
|
|
print(f"Part 1: {part1(*vals)}")
|
||
|
|
print(f"Part 2: {part2(*vals)}")
|
||
|
|
|