[adventofcode] misc snippets

2019_day_10.py

from collections import defaultdict
import numpy as np

inp1 = """.#..#
.....
#####
....#
...##"""

inp2 = """......#.#.
#..#.#....
..#######.
.#.#.###..
.#..#.....
..#....#.#
#..#....#.
.##.#..###
##...#..#.
.#....####"""

inp3 = """#.#...#.#.
.###....#.
.#....#...
##.#.#.#.#
....#.#.#.
.##..###.#
..#...##..
..##....##
......#...
.####.###."""

def parse_inp(inp=inp1):
    return np.array([[c for c in row] for row in inp.splitlines()])

def get_asteroids(grid):
    positions = []
    for i in range(grid.shape[0]):
        for j in range(grid.shape[1]):
            pos = (i,j)
            if grid[pos] == "#":
                positions.append(pos)
    return np.array(positions)

def get_unique_angles(p1, positions):
    angles = set()
    for pos in (positions - p1): # taking p1 as the origin
        x, y = pos
        if x == y == 0: # skip itself
            continue
        angle = math.atan2(y, x)
        angles.add(angle)
    return angles

def solve_1(inp=test_inp2):
    inp = parse_inp(inp)
    positions = get_asteroids(inp)
    
    angle_max = 0
    for p in positions:
        angles = get_unique_angles(p, positions)
        sum_angles = len(angles)
        if sum_angles > angle_max:
            angle_max = sum_angles

    return angle_max
    
assert solve_1(inp1) == 8    
assert solve_1(inp2) == 33
assert solve_1(inp3) == 35
solve_1(inp0)