105 lines
3.3 KiB
Python
105 lines
3.3 KiB
Python
from typing import Union, Callable
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def parse_data() -> list[str]:
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data = []
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with open("input.txt") as file:
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for line in file:
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_line = line.rstrip()
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data.append(_line)
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return data
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# Count occupied seats *adjacent* to the seat at position (x, y)
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def count_adjacent(x: int, y: int, data: list[str]) -> int:
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def check_occupied(_x: int, _y: int, _data: list[str]) -> int:
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if 0 <= _x < len(data[0]) and 0 <= _y < len(data):
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if data[_y][_x] == '#':
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return 1
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return 0
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places = [(-1, -1), (-1, 0), (-1, 1), (0, -1), (0, 1), (1, -1), (1, 0), (1, 1)]
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result = 0
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for _x, _y in places:
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result += check_occupied(x + _x, y + _y, data)
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return result
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def generate_new_grid(past_data: list[str], counting_func: Callable, threshold: int):
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output = []
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for y in range(len(past_data)):
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line = ""
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for x in range(len(past_data[0])):
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if past_data[y][x] == "#" and counting_func(x, y, past_data) >= threshold:
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new_char = 'L'
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elif past_data[y][x] == 'L' and counting_func(x, y, past_data) == 0:
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new_char = '#'
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else:
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new_char = past_data[y][x]
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line += new_char
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output.append(line)
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return output
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def find_stable_state(grid: list[str], counting_func: Callable, threshold: int = 4, limit_iter: int = 10000) -> Union[None, list[str]]:
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def is_it_different(old_data: list[str], new_data: list[str]) -> bool:
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for y in range(len(old_data)):
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for x in range(len(old_data[0])):
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if old_data[y][x] != new_data[y][x]:
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return True
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return False
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for i in range(limit_iter):
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new_state = generate_new_grid(grid, counting_func, threshold)
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if not is_it_different(grid, new_state):
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return new_state
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grid = new_state
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return None
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def solve_p1(input_data: list[str]) -> int:
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final_state = find_stable_state(input_data, counting_func=count_adjacent, threshold=4)
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if final_state is None:
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return -1
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result = 0
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for line in final_state:
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result += line.count('#')
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return result
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# Count occupied seats *raycast* from the seat at position (x, y)
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def count_raycast(x: int, y: int, data: list[str]) -> int:
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def check_occupied_ray(start: (int, int), direction: (int, int), _data: list[str]) -> int:
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curr_x, curr_y = start
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dir_x, dir_y = direction
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while 0 <= (curr_x := curr_x + dir_x) < len(data[0]) and 0 <= (curr_y := curr_y + dir_y) < len(data):
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if data[curr_y][curr_x] == '#':
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return 1
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elif data[curr_y][curr_x] == 'L':
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return 0
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return 0
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directions = [(-1, -1), (-1, 0), (-1, 1), (0, -1), (0, 1), (1, -1), (1, 0), (1, 1)]
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result = 0
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for direction in directions:
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result += check_occupied_ray((x, y), direction, data)
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return result
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def solve_p2(input_data: list[str]) -> int:
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final_state = find_stable_state(input_data, counting_func=count_raycast, threshold=5)
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if final_state is None:
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return -1
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result = 0
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for line in final_state:
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result += line.count('#')
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return result
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DATA = parse_data()
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print(solve_p1(DATA))
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print(solve_p2(DATA))
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