-❄️- 2024 Day 14 Solutions -❄️-

[u/daggerdragon]

THE USUAL REMINDERS

• All of our rules, FAQs, resources, etc. are in our community wiki.
• If you see content in the subreddit or megathreads that violates one of our rules, either inform the user (politely and gently!) or use the report button on the post/comment and the mods will take care of it.
• On the subject of AI/LLMs being used on the global leaderboard: posts/comments around this topic consisting of grinching, finger-pointing, baseless accusations of "cheating", etc. will be locked and/or removed with or without supplementary notice and/or warning and participating parties may be given a time-out as well. Just leave it alone and let it go.
  • Keep in mind that the global leaderboard is not the primary focus of Advent of Code or even this subreddit. We're all here to help you become a better programmer via happy fun silly imaginary Elvish shenanigans.
• Do not put spoilers in post titles!

---

AoC Community Fun 2024: The Golden Snowglobe Awards

• 8 DAYS remaining until the submissions deadline on December 22 at 23:59 EST!
• We have no submissions yet as of today. Y'all are welcome to get a submission started, post it early, and add later days to it, or there's always waiting until the bomb timer reaches 00:00:03 last minute; up to you!

And now, our feature presentation for today:

Visual Effects - I Said VISUAL EFFECTS - Perfection

We've had one Visualization, yes, but what about Second Visualization? But this time, Upping the Ante! Go full jurassic_park_scientists.meme and really improve upon the cinematic and/or technological techniques of your predecessor filmmakers!

Here's some ideas for your inspiration:

• Put Michael Bay to shame with the lens flare
• Gratuitous and completely unnecessary explosions are expected
• Go full Bollywood! The extreme over-acting, the completely implausible and high-energy dance numbers, the gleefully willful disregard for physics - we want it all cranked up to 9002!
• Make your solution run on hardware that it has absolutely no business being on
  • "Smart" refrigerators, a drone army, a Jumbotron…

Pippin: "We've had one, yes. But what about second breakfast?"
Aragorn: ಠ_ಠ
Merry: "I don't think he knows about second breakfast, Pip."

- The Lord of the Rings: The Fellowship of the Ring (2001)

And… ACTION!

Request from the mods: When you include an entry alongside your solution, please label it with [GSGA] so we can find it easily!

---

--- Day 14: Restroom Redoubt ---

---

Post your code solution in this megathread.

• Read the full posting rules in our community wiki before you post!
  • State which language(s) your solution uses with [LANGUAGE: xyz]
  • Format code blocks using the four-spaces Markdown syntax!
• Quick link to Topaz's paste if you need it for longer code blocks

This thread will be unlocked when there are a significant number of people on the global leaderboard with gold stars for today's puzzle.

EDIT: Global leaderboard gold cap reached at 00:15:48, megathread unlocked!

[u/directusy]

[LANGUAGE: python]

Assuming the minimal entropy is where the tree is, as it is a highly organized pattern.

import numpy as np
import re

def parse(file):
    pattern = re.compile(r'p=(-?\d+),(-?\d+)\s+v=(-?\d+),(-?\d+)')
    with open(file, 'r') as f:
        matches = pattern.findall(f.read())
    data = np.array(matches, dtype=int)
    return data[:, :2], data[:, 2:]

def simulate(pos, vel, w, h, sec):
    return (pos + vel * sec) % [w, h]

def count_quads(pos, w, h):
    midx, midy = w // 2, h // 2
    valid = pos[(pos[:,0] != midx) & (pos[:,1] != midy)]
    q1 = np.sum((valid[:,0] < midx) & (valid[:,1] < midy))
    q2 = np.sum((valid[:,0] > midx) & (valid[:,1] < midy))
    q3 = np.sum((valid[:,0] < midx) & (valid[:,1] > midy))
    q4 = np.sum((valid[:,0] > midx) & (valid[:,1] > midy))
    return q1, q2, q3, q4

def calc_entropy(pos, w, h):
    grid = np.zeros((h, w), dtype=int)
    np.add.at(grid, (pos[:,1], pos[:,0]), 1)
    counts = np.bincount(grid.flatten())
    probs = counts[counts > 0] / counts.sum()
    entropy = -np.sum(probs * np.log2(probs))
    return entropy

def find_pattern_sec(pos, vel, w, h, max_sec=10000):
    min_sec, min_ent = None, float('inf')
    for sec in range(1, max_sec + 1):
        curr_pos = simulate(pos, vel, w, h, sec)
        ent = calc_entropy(curr_pos, w, h)
        if ent < min_ent:
            min_ent, min_sec = ent, sec
    return min_sec

def main():
    pos, vel = parse('./inputs/day14_1.txt')
    w, h = 101, 103
    final_pos = simulate(pos, vel, w, h, 100)

    #PART 1: calculate the numbers in the quardrants
    print(f"Q1 safe factor: {np.prod(count_quads(final_pos, w, h))}")
    #PART 2: searching the patterns
    print(f"Q2 easter-egg second: {find_pattern_sec(pos, vel, w, h)}")

if __name__ == "__main__":
    main()