55 lines
1.7 KiB
Python
55 lines
1.7 KiB
Python
from typing import Any, Iterator
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import numpy as np
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from numpy.typing import NDArray
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from ..base import BaseSolver
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class Solver(BaseSolver):
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def solve(self, input: str) -> Iterator[Any]:
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lines = [line.strip() for line in input.splitlines()]
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trees = np.array([[int(x) for x in row] for row in lines])
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# answer 1
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highest_trees = np.ones(trees.shape + (4,), dtype=int) * -1
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highest_trees[1:-1, 1:-1] = [
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[
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[
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trees[:i, j].max(),
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trees[i + 1 :, j].max(),
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trees[i, :j].max(),
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trees[i, j + 1 :].max(),
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]
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for j in range(1, trees.shape[1] - 1)
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]
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for i in range(1, trees.shape[0] - 1)
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]
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yield (highest_trees.min(axis=2) < trees).sum()
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def viewing_distance(row_of_trees: NDArray[np.int_], value: int) -> int:
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w = np.where(row_of_trees >= value)[0]
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if not w.size:
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return len(row_of_trees)
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return w[0] + 1
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# answer 2
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v_distances = np.zeros(trees.shape + (4,), dtype=int)
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v_distances[1:-1, 1:-1, :] = [
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[
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[
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viewing_distance(trees[i - 1 :: -1, j], trees[i, j]),
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viewing_distance(trees[i, j - 1 :: -1], trees[i, j]),
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viewing_distance(trees[i, j + 1 :], trees[i, j]),
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viewing_distance(trees[i + 1 :, j], trees[i, j]),
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]
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for j in range(1, trees.shape[1] - 1)
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]
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for i in range(1, trees.shape[0] - 1)
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]
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yield np.prod(v_distances, axis=2).max()
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