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https://github.com/Crocmagnon/advent-of-code.git
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68 lines
1.9 KiB
Python
68 lines
1.9 KiB
Python
from typing import Union
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def main(filename: str, expected_part_1: int = None, expected_part_2: int = None):
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print(f"\n+ Running on {filename}")
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with open(filename) as f:
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starting_numbers = list(map(int, f.read().strip().split("\n")[0].split(",")))
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counter_part_1 = solve_part_1(starting_numbers)
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print(f"1. Found {counter_part_1}")
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if expected_part_1:
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assert expected_part_1 == counter_part_1
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counter_part_2 = solve_part_2(starting_numbers)
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print(f"2. Found {counter_part_2}")
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if expected_part_2:
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assert expected_part_2 == counter_part_2
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SeenTuple = Union[tuple[int], tuple[int, int]]
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Seen = dict[int, SeenTuple]
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def solve_part_1(starting_numbers):
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return solve(starting_numbers, 2020)
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def solve(starting_numbers, limit):
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seen = dict() # type: Seen
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previous = 0
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for turn, current in enumerate(starting_numbers):
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seen[current] = (turn,)
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previous = current
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previous_first_time = True
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for turn in range(len(starting_numbers), limit):
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if previous_first_time:
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current = 0
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else:
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current = seen[previous][0] - seen[previous][1]
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seen[current] = seen_tuple(seen, current, turn)
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previous = current
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previous_first_time = first_time_seen(seen, previous)
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return previous
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def first_time_seen(seen: Seen, previous: int) -> bool:
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return len(seen[previous]) == 1
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def seen_tuple(seen: Seen, current: int, turn: int) -> SeenTuple:
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try:
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existing = seen[current]
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return turn, existing[0]
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except KeyError:
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return (turn,)
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def solve_part_2(starting_numbers):
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return solve(starting_numbers, 30_000_000)
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if __name__ == "__main__":
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main("inputs/day15-test1", 436, 175594)
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main("inputs/day15-test2", 1, 2578)
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main("inputs/day15-test6", 438, 18)
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main("inputs/day15-test7", 1836, 362)
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main("inputs/day15", 595, 1708310)
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