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https://github.com/cupcakearmy/advent-of-code.git
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131 lines
3.2 KiB
Python
131 lines
3.2 KiB
Python
from typing import List, Union, Tuple
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Point = Tuple[int]
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Path = Tuple[Point]
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Paths = [Path]
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ALL_DIRECTIONS = (
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(1, 1),
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(1, 0),
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(1, -1),
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(0, 1),
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(0, -1),
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(-1, 1),
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(-1, 0),
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(-1, -1),
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)
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LETTER_MAP = {"X": 0, "M": 1, "A": 2, "S": 3}
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class Board:
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rows: List[List[int]]
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def __init__(self, rows: List[List[int]]):
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self.rows = rows
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self.max_y = len(self.rows)
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self.max_x = len(self.rows[0])
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def get(self, x: int, y: int) -> Union[None, int]:
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if x < 0 or y < 0:
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return None
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if x >= self.max_x or y >= self.max_y:
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return None
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return self.rows[y][x]
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# def get_neighbours(self, x: int, y: int, target: int) -> List[Point]:
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# n = []
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# for dx in range(x - 1, x + 2):
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# for dy in range(y - 1, y + 2):
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# if self.get(dx, dy) == target:
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# n.append((dx, dy))
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# return n
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@staticmethod
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def parse(raw: str):
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rows = [[LETTER_MAP[letter] for letter in line] for line in raw.splitlines()]
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return Board(rows)
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# def find_maze(b: Board, path: Path, next_char: int) -> Paths:
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# x, y = path[-1]
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# print(f"Find {x} {y} n={next_char}")
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# paths: Paths = []
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# neighbours = b.get_neighbours(x, y, next_char)
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# # Found last letter
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# if next_char == 3:
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# return [path + (n,) for n in neighbours]
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# # Recurse
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# for n in neighbours:
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# p = path + (n,)
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# sub_paths = find(b, p, next_char + 1)
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# if len(sub_paths):
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# paths = paths + sub_paths
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# return paths
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def find_line(b: Board, point: Point, direction: Point) -> Union[Path, None]:
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x, y = point
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dx, dy = direction
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path: Path = point
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for i in range(1, 4):
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px = x + (dx * i)
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py = y + (dy * i)
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if b.get(px, py) != i:
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return None
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path = path + ((x, y),)
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return path
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def find_x(b: Board, point: Point) -> bool:
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x, y = point
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for dx, dy in ALL_DIRECTIONS:
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# Check if is "M", then the opposite for "S" and the the perpendicular
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if b.get(x + dx, y + dy) == 1:
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if b.get(x - dx, y - dy) == 3:
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# Found first "MAS", check perpendicular
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p_dx = -dy
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p_dy = dx
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p_a = b.get(x + p_dx, y + p_dy)
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p_b = b.get(x - p_dx, y - p_dy)
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if (p_a == 1 and p_b == 3) or (p_a == 3 and p_b == 1):
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return True
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return False
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def solve(raw: str) -> int:
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# Part 1
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part1 = []
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part2 = 0
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b = Board.parse(raw)
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for x in range(b.max_x):
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for y in range(b.max_y):
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p = b.get(x, y)
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if p == 0:
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for direction in ALL_DIRECTIONS:
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found = find_line(b, (x, y), direction)
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if found:
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part1.append(found)
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if p == 2:
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if find_x(b, (x, y)):
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part2 += 1
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return (len(part1), part2)
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# Test
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with open("./2024/04/test.txt", "r") as f:
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result = solve(f.read().strip())
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print(result)
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# Input
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with open("./2024/04/input.txt", "r") as f:
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result = solve(f.read().strip())
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print(result)
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