advent-of-code/2022/day8.py
2022-12-08 08:59:25 +01:00

55 lines
1.3 KiB
Python

# -*- encoding: utf-8 -*-
import sys
import numpy as np
lines = sys.stdin.read().splitlines()
trees = np.array([[int(x) for x in row] for row in lines])
# answer 1
highest_trees = np.ones(trees.shape + (4,), dtype=int) * -1
highest_trees[1:-1, 1:-1] = [
[
[
trees[:i, j].max(),
trees[i + 1 :, j].max(),
trees[i, :j].max(),
trees[i, j + 1 :].max(),
]
for j in range(1, trees.shape[1] - 1)
]
for i in range(1, trees.shape[0] - 1)
]
answer_1 = (highest_trees.min(axis=2) < trees).sum()
print(f"answer 1 is {answer_1}")
def viewing_distance(row_of_trees: np.ndarray, value: int) -> int:
w = np.where(row_of_trees >= value)[0]
if not w.size:
return len(row_of_trees)
return w[0] + 1
# answer 2
v_distances = np.zeros(trees.shape + (4,), dtype=int)
v_distances[1:-1, 1:-1, :] = [
[
[
viewing_distance(trees[i - 1 :: -1, j], trees[i, j]),
viewing_distance(trees[i, j - 1 :: -1], trees[i, j]),
viewing_distance(trees[i, j + 1 :], trees[i, j]),
viewing_distance(trees[i + 1 :, j], trees[i, j]),
]
for j in range(1, trees.shape[1] - 1)
]
for i in range(1, trees.shape[0] - 1)
]
answer_2 = np.prod(v_distances, axis=2).max()
print(f"answer 2 is {answer_2}")