day14 easter egg

2024/day14/README.md

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+# The EEHQ Christmas Tree
+
+![christmas tree](christmastree.gif)

2024/day14/easteregg.py

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+#!/usr/bin/env python3
+# [Day 14: Restroom Redoubt](https://adventofcode.com/2024/day/14)
+
+import itertools
+import re
+import sys
+from collections import defaultdict
+from dataclasses import dataclass
+from pathlib import Path
+from random import randint, seed
+
+from imgcat import imgcat
+from PIL import Image
+
+filename = sys.argv[1] if len(sys.argv) > 1 else "input.txt"
+data = Path(filename).read_text().strip()
+lines = data.splitlines()
+
+# to always make the same picture with a given input
+seed(sum(map(ord, filename)))
+
+
+@dataclass
+class Robot:
+    px: int
+    py: int
+    vx: int
+    vy: int
+
+
+robots = []
+for line in lines:
+    m = re.match(r"p=(\d+),(\d+) v=(-?\d+),(-?\d+)", line)
+    px, py, vx, vy = map(int, m.groups())
+    robots.append(Robot(px, py, vx, vy))
+
+width = 101
+height = 103
+
+for n in itertools.count(5000):
+
+    grid = defaultdict(int)
+    for robot in robots:
+        px = (robot.px + robot.vx * n) % width
+        py = (robot.py + robot.vy * n) % height
+
+        if (px, py) in grid:
+            break
+
+        grid[px, py] = 1
+    else:
+        break
+
+picture = Image.new("RGB", (width, height))
+for y in range(height):
+    for x in range(width):
+        if grid[x, y] != 0:
+            h = sum(grid[x + i, y] for i in range(-4, 5))
+            v = sum(grid[x, y + i] for i in range(-4, 5))
+
+            if h >= 5 or v >= 5:
+                picture.putpixel((x, y), (0, 255, 0))
+            else:
+                picture.putpixel((x, y), (255, randint(0, 255), 0))
+
+picture.save("christmastree.png")
+imgcat(picture)

2024/day14/easteregg_anim.sh

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+#!/usr/bin/env bash
+
+set -euo pipefail
+
+i=0
+declare -a frames=()
+for input in ../../data/*/2024/14.in ; do
+    i=$((i+1))
+
+    ./easteregg.py $input
+
+    mv christmastree.png frame$i.png
+    frames+=(frame$i.png)
+done
+
+magick -delay 50 -loop 1 ${frames[*]} christmastree.gif
+rm ${frames[*]}