diff --git a/2017/d11/ex2/ex2.py b/2017/d11/ex2/ex2.py new file mode 100755 index 0000000..9355eaa --- /dev/null +++ b/2017/d11/ex2/ex2.py @@ -0,0 +1,66 @@ +#!/usr/bin/env python + +import enum +import sys +from collections.abc import Iterator +from typing import NamedTuple + + +class Point(NamedTuple): + x: int + y: int + + +class Direction(enum.StrEnum): + NORTH_WEST = "nw" + NORTH = "n" + NORTH_EAST = "ne" + SOUTH_EAST = "se" + SOUTH = "s" + SOUTH_WEST = "sw" + + # https://www.redblobgames.com/grids/hexagons/#coordinates-axial + def apply(self, p: Point) -> Point: + # (x, y) <=> (q, r) + match self: + case Direction.NORTH_WEST: + dx, dy = -1, 0 + case Direction.NORTH: + dx, dy = 0, -1 + case Direction.NORTH_EAST: + dx, dy = 1, -1 + case Direction.SOUTH_EAST: + dx, dy = 1, 0 + case Direction.SOUTH: + dx, dy = 0, 1 + case Direction.SOUTH_WEST: + dx, dy = -1, 1 + return Point(p.x + dx, p.y + dy) + + +def solve(input: str) -> int: + def parse(input: str) -> list[Direction]: + return [Direction(dir) for dir in input.strip().split(",")] + + # https://www.redblobgames.com/grids/hexagons/#distances-axial + def hex_dist(a: Point, b: Point) -> int: + dx, dy = a.x - b.x, a.y - b.y + return (abs(dx) + abs(dx + dy) + abs(dy)) // 2 + + def walk(directions: list[Direction]) -> Iterator[Point]: + pos = Point(0, 0) + for dir in directions: + pos = dir.apply(pos) + yield pos + + directions = parse(input) + return max(hex_dist(p, Point(0, 0)) for p in walk(directions)) + + +def main() -> None: + input = sys.stdin.read() + print(solve(input)) + + +if __name__ == "__main__": + main()