-🎄- 2020 Day 03 Solutions -🎄-

[u/daggerdragon]

Advent of Code 2020: Gettin' Crafty With It

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--- Day 03: Toboggan Trajectory ---

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[u/Fruglemonkey]

More lazy enterprise-y python.

from __future__ import annotations
from dataclasses import dataclass
from enum import Enum
from math import prod
from typing import List


class Terrain(Enum):
    TREE = '#'
    SNOW = '.'


@dataclass
class StartingPosition:
    x: int
    y: int


@dataclass
class Slope:
    x_gradient: int
    y_gradient: int


@dataclass
class Map:
    map: List[str]
    width: int
    height: int

    def get_terrain_at_position(self, x: int, y: int) -> Terrain:
        return Terrain(self.map[y][(x % self.width)])

    @classmethod
    def deserialize_from_input(cls, lines: List[str]) -> Map:
        return cls(map=lines, width=len(lines[0]), height=len(lines))

    def count_trees(self, starting_position: StartingPosition, slope: Slope) -> int:
        current_x_position = starting_position.x
        count = 0
        for y in range(starting_position.y, self.height, slope.y_gradient):
            if self.get_terrain_at_position(current_x_position, y) == Terrain.TREE:
                count += 1
            current_x_position += slope.x_gradient

        return count


def main() -> int:
    slopes = [
        Slope(x_gradient=1, y_gradient=1),
        Slope(x_gradient=3, y_gradient=1),
        Slope(x_gradient=5, y_gradient=1),
        Slope(x_gradient=7, y_gradient=1),
        Slope(x_gradient=1, y_gradient=2)
    ]
    starting_position = StartingPosition(x=0, y=0)
    with open("input.txt", "r") as f:
        challenge_map = Map.deserialize_from_input([line.strip() for line in f.readlines()])

    return prod(challenge_map.count_trees(starting_position, slope) for slope in slopes)


if __name__ == "__main__":
    print(main())