2022: Add day 14.

HoffmannChristian · HoffmannChristian · commit 1b0763565bc5 · 2022-12-22T14:28:02.000+01:00
diff --git a/2022/advent_of_code_2022.ipynb b/2022/advent_of_code_2022.ipynb
@@ -1012,6 +1012,109 @@
     "divider_packet_idx = [pairs.index(packet)+1 for packet in divider_packets]\n",
     "reduce(mul, divider_packet_idx)"
    ]
+  },
+  {
+   "attachments": {},
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Day 14: Regolith Reservoir\n",
+    "\n",
+    "How many units of sand come to rest before sand starts flowing into the abyss below?"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "from re import split\n",
+    "\n",
+    "def get_rock(lines):\n",
+    "    rock = set()\n",
+    "    for line in lines:\n",
+    "        numbers = split(r'\\D+', line)\n",
+    "        for i in range(0, len(numbers)-2, 2):\n",
+    "            x1 = int(numbers[i:i+1][0])\n",
+    "            y1 = int(numbers[i+1:i+2][0])\n",
+    "            x2 = int(numbers[i+2:i+3][0])\n",
+    "            y2 = int(numbers[i+3:i+4][0])\n",
+    "            start_x, end_x = min(x1, x2), max(x1, x2)\n",
+    "            start_y, end_y = min(y1, y2), max(y1, y2)\n",
+    "            for x in range(start_x, end_x+1):\n",
+    "                for y in range(start_y, end_y+1):\n",
+    "                    rock.add((x,y))\n",
+    "    return rock\n",
+    "\n",
+    "def get_ground_level(rocks):\n",
+    "    return max([rock[1] for rock in rocks])\n",
+    "\n",
+    "def move_grain(grain, blocked):\n",
+    "    y = grain[1]+1\n",
+    "    down = (grain[0], y)\n",
+    "    if down not in blocked:\n",
+    "        return down\n",
+    "    diagonal_left = (grain[0]-1, y)\n",
+    "    if diagonal_left not in blocked:\n",
+    "        return diagonal_left\n",
+    "    diagonal_right = (grain[0]+1, y)\n",
+    "    if diagonal_right not in blocked:\n",
+    "        return diagonal_right\n",
+    "    return None\n",
+    "\n",
+    "lines = open('14_input.txt', 'r').readlines()\n",
+    "lines = [line.strip() for line in lines]\n",
+    "\n",
+    "rocks = get_rock(lines)\n",
+    "ground_level = get_ground_level(rocks)\n",
+    "\n",
+    "resting_sand = set()\n",
+    "grain = (500, 0)\n",
+    "\n",
+    "while grain[1] <= ground_level:\n",
+    "    moved_grain = move_grain(grain, rocks.union(resting_sand))\n",
+    "    if moved_grain is None:\n",
+    "        resting_sand.add(grain)\n",
+    "        grain = (500, 0)\n",
+    "    else:\n",
+    "        grain = moved_grain\n",
+    "\n",
+    "len(resting_sand)"
+   ]
+  },
+  {
+   "attachments": {},
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "How many units of sand come to rest?"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "rocks_and_sand = get_rock(lines)\n",
+    "num_rocks = len(rocks_and_sand)\n",
+    "ground_level = get_ground_level(rocks) + 2\n",
+    "\n",
+    "grain = (500, 0)\n",
+    "while True:\n",
+    "    moved_grain = move_grain(grain, rocks_and_sand)\n",
+    "    if moved_grain is None and grain == (500, 0):\n",
+    "        rocks_and_sand.add(grain)\n",
+    "        break\n",
+    "    if moved_grain is None or moved_grain[1] == ground_level:\n",
+    "        rocks_and_sand.add(grain)\n",
+    "        grain = (500, 0)\n",
+    "    else:\n",
+    "        grain = moved_grain\n",
+    "\n",
+    "len(rocks_and_sand) - num_rocks"
+   ]
   }
  ],
  "metadata": {
