59 lines
1.3 KiB
Python
59 lines
1.3 KiB
Python
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import sys
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from pprint import pprint
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from copy import deepcopy
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def shift(map, dx, dy):
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swapped = True
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while swapped:
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swapped = False
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for y in range(max(0, -dy), len(map) - max(0, dy)):
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for x in range(max(0, -dx), len(map) - max(0, dx)):
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if map[y + dy][x + dx] == "." and map[y][x] == "O":
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map[y + dy][x + dx] = "O"
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map[y][x] = "."
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swapped = True
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def weigh(map):
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return sum((len(map) - y) * row.count("O") for (y, row) in enumerate(map))
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CYCLES = 1_000_000_000
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def main():
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with open(sys.argv[1]) as f:
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map = [list(l) for l in f.read().strip().splitlines()]
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part1 = 0
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shift(map, 0, -1)
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part1 = weigh(map)
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seen = {}
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history = []
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for i in range(CYCLES):
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shift(map, 0, -1)
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if i == 0: pprint(map)
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shift(map, -1, 0)
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if i == 0: pprint(map)
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shift(map, 0, 1)
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if i == 0: pprint(map)
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shift(map, 1, 0)
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if i == 0: pprint(map)
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s = str(map)
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if s in seen:
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break
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seen[s] = i
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history.append(weigh(map))
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j = seen[s]
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offset = (CYCLES - j) % (i + 1 - j) + j
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part2 = history[offset]
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print(part1, part2)
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main()
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# 98887 too low
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# 98898 too high
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# 103761 too high
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