54 lines
1.6 KiB
Python
54 lines
1.6 KiB
Python
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#!/bin/python
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from logging import debug, DEBUG, basicConfig
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from sys import argv
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from re import finditer
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def parse_input(input_filepath: str) -> list[str]:
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with open(file=input_filepath, mode="r") as input_file:
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input_data: list[str] = input_file.readlines()
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return [s.strip() for s in input_data]
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def find_split_count(grid: list[str]) -> int:
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beams: set[int] = set([grid[0].find("S")])
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split_count = 0
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for row in grid[1:]:
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splitters: set[int] = set([i.start(0) for i in finditer("\\^", row)])
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if not splitters:
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debug(
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f"{"".join(list[str](map(lambda x: "|" if x in beams else ("^" if x in splitters else "."), range(len(grid)))))}"
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)
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continue
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intersections = beams.intersection(splitters)
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differences = beams.difference(splitters)
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split_count += len(intersections)
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beams = (
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set([x - 1 for x in intersections if x > 0])
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.union([x + 1 for x in intersections if x < len(grid) - 2])
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.union(differences)
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.difference(splitters)
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)
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debug(
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f"{"".join(list[str](map(lambda x: "|" if x in beams else ("^" if x in splitters else "."), range(len(grid)))))}"
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)
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return split_count
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def main() -> None:
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input_filepath = "input/grid.txt"
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input_grid = parse_input(input_filepath)
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split_count = find_split_count(input_grid)
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print(f"The beam splits {split_count} times.")
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return
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if __name__ == "__main__":
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if "-d" in argv or "--debug" in argv:
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basicConfig(filename="debug.log", level=DEBUG)
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main()
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exit(0)
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