day3.py

import aoc

from typing import NamedTuple


class Point(NamedTuple):
    x: int
    y: int

    def up(self, distance):
        for p in range(1, distance + 1):
            yield Point(self.x, self.y + p)

    def down(self, distance):
        for p in range(1, distance + 1):
            yield Point(self.x, self.y - p)

    def right(self, distance):
        for p in range(1, distance + 1):
            yield Point(self.x + p, self.y)

    def left(self, distance):
        for p in range(1, distance + 1):
            yield Point(self.x - p, self.y)


def main():
    with aoc.open_input(__name__) as f:
        line1 = f.readline().split(',')
        line2 = f.readline().split(',')
        execute(line1, line2)


def test():
    test0 = ["R8,U5,L5,D3", "U7,R6,D4,L4"]
    execute(*(line.split(',') for line in test0))
    test1 = ["R75,D30,R83,U83,L12,D49,R71,U7,L72", "U62,R66,U55,R34,D71,R55,D58,R83"]
    execute(*(line.split(',') for line in test1))
    test2 = ["R98,U47,R26,D63,R33,U87,L62,D20,R33,U53,R51", "U98,R91,D20,R16,D67,R40,U7,R15,U6,R7"]
    execute(*(line.split(',') for line in test2))


def run_path(line):
    last_point = Point(0, 0)
    path = []
    visited = {}
    i = 0
    for dir in line:
        vec, dist = dir[0], int(dir[1:])
        if vec == 'U':
            points = last_point.up(dist)
        elif vec == 'D':
            points = last_point.down(dist)
        elif vec == 'L':
            points = last_point.left(dist)
        elif vec == 'R':
            points = last_point.right(dist)
        else:
            raise Exception("Unknown direction " + vec)

        for p in points:
            i += 1
            if p not in visited:
                visited[p] = i
            path.append(p)

        last_point = path[len(path) - 1]

    return set(path), visited


def calculate_interceptions(line1, line2):
    path1, visited1 = run_path(line1)
    path2, visited2 = run_path(line2)

    path_intersect = path1.intersection(path2)
    return path_intersect, visited1, visited2


def execute(line1, line2):
    intercepts, v1, v2 = calculate_interceptions(line1, line2)

    def distance(p):
        return abs(p.x) + abs(p.y)

    def speed(p):
        return v1[p] + v2[p]

    closest_point = min(intercepts, key=distance)
    print("Closest:", closest_point, "distance:", distance(closest_point), "speed:", speed(closest_point))

    fastest_point = min(intercepts, key=speed)
    print("Fastest:", fastest_point, "distance:", distance(fastest_point), "speed:", speed(fastest_point))