52 lines
1.4 KiB
Python
52 lines
1.4 KiB
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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from collections import defaultdict
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from typing import NamedTuple
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class Point(NamedTuple):
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x: int
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y: int
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def solve(input: str) -> int:
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def parse(input: list[str]) -> dict[str, set[Point]]:
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res: dict[str, set[Point]] = defaultdict(set)
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for x, line in enumerate(input):
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for y, c in enumerate(line):
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if c == ".":
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continue
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res[c].add(Point(x, y))
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return res
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def find_antinodes(grid: dict[str, set[Point]], dims: Point) -> set[Point]:
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max_x, max_y = dims
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antinodes: set[Point] = set()
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for antennas in grid.values():
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for start, end in itertools.permutations(antennas, 2):
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dx, dy = end.x - start.x, end.y - start.y
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for i in itertools.count():
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x, y = start.x - dx * i, start.y - dy * i
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if not (0 <= x < max_x):
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break
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if not (0 <= y < max_y):
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break
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antinodes.add(Point(x, y))
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return antinodes
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lines = input.splitlines()
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max_x, max_y = len(lines), len(lines[0])
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grid = parse(lines)
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return len(find_antinodes(grid, Point(max_x, max_y)))
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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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