46 lines
1.1 KiB
Python
Executable file
46 lines
1.1 KiB
Python
Executable file
#!/usr/bin/env python
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import copy
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import sys
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def solve(input: str) -> int:
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def parse(input: str) -> list[int]:
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return [int(n) for n in input.split(",")]
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def run_round(lengths: list[int], circle: list[int]) -> list[int]:
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circle = copy.deepcopy(circle)
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cur_pos = 0
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skip_size = 0
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for n in lengths:
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# Invalid length
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if n > len(circle):
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continue
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# Reverse
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for i, j in zip(
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range(cur_pos, cur_pos + n // 2),
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# Avoid off-by-one by going further than necessary
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range(cur_pos + n - 1, cur_pos, -1),
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):
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i %= len(circle)
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j %= len(circle)
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circle[i], circle[j] = circle[j], circle[i]
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# Move
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cur_pos += n + skip_size
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# Increase
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skip_size += 1
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return circle
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lengths = parse(input)
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circle = list(range(256))
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circle = run_round(lengths, circle)
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return circle[0] * circle[1]
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def main() -> None:
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input = sys.stdin.read()
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print(solve(input))
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if __name__ == "__main__":
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main()
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