AdventOfCode/2019/day10.py

import math

import numpy as np


DIM = 40


def main():
    with open("day10.txt", "rt") as input_file:
        amap = [line.rstrip() for line in input_file.readlines()]

    asteroids = []
    for y, line in enumerate(amap):
        for x, value in enumerate(line):
            if value == "#":
                asteroids.append((x, y))

    # Part 1
    best_vis = 0
    best_pos = None
    for pos in asteroids:
        vis = num_visible_asts(asteroids, pos)
        if vis > best_vis:
            best_vis, best_pos = vis, pos
    print(f"Best visibility is {best_vis} at {best_pos}.")
    draw(asteroids, best_pos)

def draw(asteroids, station_pos):
    for y in range(DIM):
        print(str(y).zfill(2), end=" ")
        for x in range(DIM):
            if (x, y) == station_pos:
                print("@", end="")
            elif (x, y) in asteroids:
                print("█", end="")
            else:
                print(" ", end="")
        print()
    print("  " + "0123456789"*4)

def num_visible_asts(asts, ref):
    asts = asts.copy()
    asts.remove(ref)
    angles = [np.angle(np.complex(ast[0] - ref[0], ast[1] - ref[1])) for ast in asts]
    return len(set(angles))


if __name__ == "__main__":
    main()