32 lines
646 B
Python
Executable file
32 lines
646 B
Python
Executable file
#!/usr/bin/env python
|
|
|
|
import itertools
|
|
import sys
|
|
|
|
|
|
def solve(input: str) -> int:
|
|
def parse(input: list[str]) -> list[int]:
|
|
return [int(n) for n in input]
|
|
|
|
def find_duplicate(deltas: list[int]) -> int:
|
|
start = 0
|
|
seen = {start}
|
|
for delta in itertools.cycle(deltas):
|
|
start += delta
|
|
if start in seen:
|
|
return start
|
|
seen.add(start)
|
|
assert False # Sanity check
|
|
|
|
deltas = parse(input.splitlines())
|
|
return find_duplicate(deltas)
|
|
|
|
|
|
def main() -> None:
|
|
input = sys.stdin.read()
|
|
print(solve(input))
|
|
|
|
|
|
if __name__ == "__main__":
|
|
main()
|