Files
adventofcode/2024/src/aoc/days/day4.py
2024-12-04 12:27:06 +01:00

70 lines
1.7 KiB
Python

import numpy
from . import SeparateRunner
class DayRunner(SeparateRunner):
@classmethod
def part1(cls, input: str) -> int:
grid = numpy.array(list(map(list, input.strip().split("\n"))))
found = 0
directions = [
(-1, -1),
(-1, 0),
(-1, 1),
(0, -1),
(0, 1),
(1, -1),
(1, 0),
(1, 1),
]
word = "XMAS"
for y in range(grid.shape[0]):
for x in range(grid.shape[1]):
if grid[y, x] != "X":
continue
for dx, dy in directions:
end_x = x + 3 * dx
end_y = y + 3 * dy
if (
end_x < 0
or end_x >= grid.shape[1]
or end_y < 0
or end_y >= grid.shape[0]
):
continue
if all(
grid[y + i * dy, x + i * dx] == c for i, c in enumerate(word)
):
found += 1
return found
@classmethod
def part2(cls, input: str) -> int:
grid = numpy.array(list(map(list, input.strip().split("\n"))))
found = 0
magic = ord("M") ^ ord("S")
for y in range(1, grid.shape[0] - 1):
for x in range(1, grid.shape[1] - 1):
if grid[y, x] != "A":
continue
first_diag = ord(grid[y - 1, x - 1]) ^ ord(grid[y + 1, x + 1])
secnd_diag = ord(grid[y - 1, x + 1]) ^ ord(grid[y + 1, x - 1])
if first_diag == magic and secnd_diag == magic:
found += 1
return found