59 lines
1.3 KiB
Python
59 lines
1.3 KiB
Python
from enum import Enum
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from typing import Tuple, Iterable
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import aoc
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HexPos = Tuple[int, int, int]
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class Direction(Enum):
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N = 0
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NE = 1
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SE = 2
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S = 3
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SW = 4
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NW = 5
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@classmethod
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def parse(cls, s: str):
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match s:
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case 'n': return Direction.N
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case 's': return Direction.S
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case 'ne': return Direction.NE
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case 'nw': return Direction.NW
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case 'se': return Direction.SE
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case 'sw': return Direction.SW
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case _: raise ValueError(f"unknown direction: {s}")
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def part1():
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steps = map(Direction.parse, aoc.puzzle_input(11).split(","))
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return distance(walk(steps))
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def walk(steps: Iterable[Direction]) -> HexPos:
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pos = (0, 0, 0)
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for step in steps:
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pos = move(pos, step)
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return pos
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def distance(pos: HexPos) -> int:
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assert sum(pos) == 0, pos
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return sum(map(abs, pos)) // 2
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def move(pos: HexPos, dir: Direction) -> HexPos:
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(q, r, s) = pos
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match dir:
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case Direction.N: return (q, r-1, s+1)
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case Direction.S: return (q, r+1, s-1)
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case Direction.NE: return (q+1, r-1, s)
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case Direction.SW: return (q-1, r+1, s)
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case Direction.NW: return (q-1, r, s+1)
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case Direction.SE: return (q+1, r, s-1)
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print(part1())
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