11/2024

Author: breadadams

2024/11/index.ts

@@ -0,0 +1,75 @@
+import { getPuzzle } from "../../utils";
+
+const puzzleInput = getPuzzle(__dirname).trim();
+
+const stones = puzzleInput.split(" ");
+
+const blink = (
+  stone: string,
+  blinkCount: number,
+  cache: Map<string, number>
+) => {
+  const nextBlinkCount = blinkCount - 1;
+
+  if (nextBlinkCount >= 0) {
+    const cacheKey = `${stone}.${blinkCount}`;
+
+    if (cache.has(cacheKey)) {
+      return cache.get(cacheKey);
+    }
+
+    if (stone === "0") {
+      const res = blink("1", nextBlinkCount, cache);
+      cache.set(cacheKey, res);
+      return res;
+    }
+
+    if (stone.length % 2 === 0) {
+      const center = stone.length / 2;
+
+      const newStone1 = stone.substring(0, center);
+      const newStone2 = `${Number(stone.substring(center, stone.length))}`;
+
+      const res1 = blink(newStone1, nextBlinkCount, cache);
+      const res2 = blink(newStone2, nextBlinkCount, cache);
+      const res = res1 + res2;
+
+      cache.set(cacheKey, res);
+      return res;
+    }
+
+    const res = blink(`${Number(stone) * 2024}`, nextBlinkCount, cache);
+    cache.set(cacheKey, res);
+
+    return res;
+  }
+
+  return 1;
+};
+
+const countStones = (blinks: number) => {
+  const cache = new Map<string, number>();
+  let count = 0;
+
+  for (const stone of stones) {
+    count += blink(stone, blinks, cache);
+  }
+
+  return count;
+};
+
+// Part 1
+(() => {
+  console.time("part 1");
+  const stoneCount = countStones(25);
+  console.log("part 1 stoneCount >>>", stoneCount);
+  console.timeEnd("part 1");
+})();
+
+// Part 2
+(() => {
+  console.time("part 2");
+  const stoneCount = countStones(75);
+  console.log("part 2 stoneCount >>>", stoneCount);
+  console.timeEnd("part 2");
+})();

README.md

@@ -6,6 +6,7 @@
 
 |                    Day                     | Part 1 | Part 2 |
 | :----------------------------------------: | :----: | :----: |
+| [11](https://adventofcode.com/2024/day/11) |   ✅   |   ✅   |
 | [10](https://adventofcode.com/2024/day/10) |   ✅   |   ✅   |
 | [09](https://adventofcode.com/2024/day/9)  |   ✅   |   ✅   |
 | [08](https://adventofcode.com/2024/day/8)  |   ✅   |   ✅   |