32 lines
646 B
Python
32 lines
646 B
Python
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#!/usr/bin/env python
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import itertools
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import sys
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def solve(input: str) -> int:
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def parse(input: list[str]) -> list[int]:
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return [int(n) for n in input]
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def find_duplicate(deltas: list[int]) -> int:
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start = 0
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seen = {start}
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for delta in itertools.cycle(deltas):
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start += delta
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if start in seen:
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return start
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seen.add(start)
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assert False # Sanity check
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deltas = parse(input.splitlines())
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return find_duplicate(deltas)
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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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