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from __future__ import annotations |
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2
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3
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import pathlib |
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4
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from typing import Literal, cast, Set, Tuple |
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5
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6
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7
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class Point: |
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8
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9
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def __init__(self, x, y): |
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self.previous = None |
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11
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self.x = x |
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12
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self.y = y |
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13
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14
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def is_touching(self, other: Point) -> bool: |
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return ( |
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self.x == other.x and self.y == other.y |
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or ( |
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abs(self.x - other.x) < 2 |
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and abs(self.y - other.y) < 2 |
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) |
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) |
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23
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def move(self, x: int, y: int): |
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24
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self.previous = Point(self.x, self.y) |
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self.x += x |
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26
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self.y += y |
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27
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28
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def copy(self, other: Point): |
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self.previous = Point(self.x, self.y) |
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self.x = other.x |
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31
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self.y = other.y |
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32
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33
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34
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class Rope: |
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35
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36
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def __init__(self, knots: int): |
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if knots < 2: |
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raise ValueError('Rope must have at least 2 knots') |
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39
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40
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self.knots = [Point(0, 0) for _ in range(knots)] |
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41
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self.prints: Set[Tuple[int, int]] = set() |
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42
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43
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@property |
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def head(self) -> Point: |
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return self.knots[0] |
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47
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@property |
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48
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def tail(self) -> Point: |
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return self.knots[-1] |
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51
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def move_head(self, direction: Literal['L', 'R', 'U', 'D']): |
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dx: int = (direction == 'L') - (direction == 'R') |
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dy: int = (direction == 'U') - (direction == 'D') |
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54
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55
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self.head.move(dx, dy) |
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56
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self.propagate_movement() |
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57
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58
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self.prints.add((self.tail.x, self.tail.y)) |
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59
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60
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def propagate_movement(self): |
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61
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for head, tail in zip(self.knots, self.knots[1:]): |
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if not tail.is_touching(head): |
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63
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tail.copy(head.previous) |
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64
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65
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def solve(self, lines) -> int: |
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66
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for line in lines: |
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move = cast(Literal['L', 'R', 'U', 'D'], line[0]) |
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68
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value = int(line[1:]) |
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69
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70
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for i in range(value): |
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71
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self.move_head(move) |
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72
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73
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return len(self.prints) |
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74
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75
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76
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def main(): |
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77
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content = pathlib.Path('./input.txt').read_text() |
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78
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lines = content.splitlines() |
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79
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80
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rope = Rope(2) |
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81
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print("Part 1:", rope.solve(lines)) |
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82
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83
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84
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if __name__ == '__main__': |
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main() |
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86
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Sigmanificient /
aoc
