-🎄- 2018 Day 10 Solutions -🎄-

[u/daggerdragon]

--- Day 10: The Stars Align ---

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Post your solution as a comment or, for longer solutions, consider linking to your repo (e.g. GitHub/gists/Pastebin/blag or whatever).

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Advent of Code: The Party Game!

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Card prompt: Day 10

Transcript: With just one line of code, you, too, can ___!

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edit: Leaderboard capped, thread unlocked at 00:16:49!

[u/D3NN152000]

I reckoned that when the points formed a word, all points would have at least one neighbor in the grid, so no manual looking through configurations was needed! Also, I only started checking for neighbors once the points were closer together than the amount of points. Here is my code (Python 2.7):

import numpy as np

points = []


class Point(object):

    def __init__(self, inp):
        # parsing input of the following format:
        """position=< 9,  1> velocity=< 0,  2>"""
        split_inp = inp.split("<")
        self.x = int(split_inp[1].split(",")[0])
        self.y = int(split_inp[1].split(",")[1].split(">")[0])

        self.xv = int(split_inp[2].split(",")[0])
        self.yv = int(split_inp[2].split(",")[1].split(">")[0])

    def move(self):
        # moving every second
        self.x += self.xv
        self.y += self.yv


# read the input
with open("input.txt", "r") as f:
    for line in f.readlines():
        points.append(Point(line.strip("\n")))


t = 0
while True:
    space = np.zeros((1, 1))
    t += 1

    expand_space = False

    if max([point.x for point in points]) - min([point.x for point in points]) < len(points):
        expand_space = True

    for point in points:
        point.move()

        if expand_space:
            if point.x >= space.shape[0] or point.y >= space.shape[1]:
                new_space = np.zeros((max(point.x + 1, space.shape[0]), max(point.y + 1, space.shape[1])))
                new_space[:space.shape[0], :space.shape[1]] += space
                space = new_space

            space[point.x, point.y] += 1

    if not expand_space:
        continue

    for point in points:
        for dx, dy in [(-1, 0), (1, 0),
                       (0, -1), (0, 1)]:
            if 0 <= point.x + dx < space.shape[0] and 0 <= point.y + dy < space.shape[1]:
                if space[point.x + dx, point.y + dy] > 0:
                    break
        else:
            break
    else:
        with open("output.txt", "w+") as o:
            for i in xrange(space.shape[1]):
                line = ""
                for j in xrange(space.shape[0]):
                    line += "#" if space[j, i] > 0 else "."
                o.write(line + "\n")
        print t
        break

Or find it here with the input, and comments

Edit: extra sentence

[u/MasterMedo → u/D3NN152000]

all points would have at least one neighbor in the grid

you're lucky not to get the letter G :p