51 lines
1.3 KiB
Python
51 lines
1.3 KiB
Python
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from sys import argv
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from scipy.ndimage import uniform_filter
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from scipy.signal import fftconvolve
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import numpy
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try:
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SERIAL = int(argv[1])
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except (ValueError, IndexError):
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print(f"Usage: {argv[0]} [serial]")
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# Build the grid.
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grid = numpy.zeros((300, 300), dtype=numpy.int32)
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for y, row in enumerate(grid):
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rack_id = numpy.arange(1, 301, dtype=numpy.int32) + 10
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power_level = (rack_id * (y + 1) + SERIAL) * rack_id
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power_level = power_level // 100 % 10 - 5
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grid[y] = power_level
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def main(from_, to=None):
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max_y, max_x = None, None
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max_size = 0
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max_value = 0
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if to is None:
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to = from_ + 1
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for size in range(from_, to):
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# Calculate the totals by convolving with a filter with ones.
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filter_ = numpy.ones((size, size), dtype=int)
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totals = fftconvolve(grid, filter_, "valid")
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# Find the indices of the maximum value.
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y, x = numpy.unravel_index(totals.argmax(), totals.shape)
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value = totals[y, x]
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if value > max_value:
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max_size, max_y, max_x = size, y, x
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max_value = value
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if to == from_ + 1:
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# If the range is one, it was part 1.
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print(f"{max_x + 1},{max_y + 1}")
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else:
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print(f"{max_x + 1},{max_y + 1},{max_size}")
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print("part 1:")
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main(3)
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print("part 2:")
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main(1, 100)
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