70 lines
1.5 KiB
Python
Executable file
70 lines
1.5 KiB
Python
Executable file
#!/usr/bin/env python
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import sys
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from dataclasses import dataclass
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from typing import List, Tuple
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Instruction = Tuple[str, int]
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Position = Tuple[int, int]
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@dataclass
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class Ship:
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pos: Position
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rel_waypoint: Position
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ORIENTATIONS = ["N", "W", "S", "E"]
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MOVES = {
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"N": (1, 0),
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"W": (0, -1),
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"S": (-1, 0),
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"E": (0, 1),
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}
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def move_ship(pos: Ship, instr: Instruction) -> Ship:
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if instr[0] == "L":
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assert instr[1] % 90 == 0
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turns = instr[1] // 90
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x, y = pos.rel_waypoint
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for __ in range(turns):
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x, y = y, -x
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return Ship(pos.pos, (x, y))
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elif instr[0] == "R":
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assert instr[1] % 90 == 0
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turns = instr[1] // 90
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x, y = pos.rel_waypoint
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for __ in range(turns):
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x, y = -y, x
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return Ship(pos.pos, (x, y))
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elif instr[0] == "F":
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dx, dy = pos.rel_waypoint
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x, y = pos.pos
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x += dx * instr[1]
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y += dy * instr[1]
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return Ship((x, y), pos.rel_waypoint)
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else:
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dx, dy = MOVES[instr[0]]
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x, y = pos.rel_waypoint
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x += dx * instr[1]
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y += dy * instr[1]
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return Ship(pos.pos, (x, y))
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def solve(raw: List[str]) -> int:
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instructions = [(i[0], int(i[1:])) for i in raw]
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ship = Ship((0, 0), (1, 10))
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for i in instructions:
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ship = move_ship(ship, i)
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return sum(abs(c) for c in ship.pos)
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def main() -> None:
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input = [line.strip() for line in sys.stdin.readlines()]
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print(solve(input))
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if __name__ == "__main__":
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main()
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