day 11; straightforward

11/index.ts

@@ -0,0 +1,62 @@
+import fs from "node:fs";
+import { printTime, now, toNum } from "../util";
+
+const test = false;
+
+const data = fs.readFileSync(
+  test ? "./inputs/testinput" : "./inputs/input",
+  "utf8"
+);
+
+let stones = data
+  .split("\n")
+  .slice(0, -1)[0]
+  .split(" ")
+  .reduce((stones, stone) => {
+    stones[stone] = 1;
+    return stones;
+  }, {});
+
+const iterate = (
+  stones: Record<string, number>,
+  blinks: number
+): Record<string, number> => {
+  for (let index = 0; index < blinks; index++) {
+    let newStones = {
+      "1": stones["0"] ? stones["0"] : 0,
+    };
+    Object.entries(stones).forEach(([stone, count]) => {
+      if (stone.length % 2 === 0) {
+        let stoneA = toNum(stone.slice(0, stone.length / 2)).toString();
+        let stoneB = toNum(stone.slice(stone.length / 2)).toString();
+        newStones[stoneA]
+          ? (newStones[stoneA] += count)
+          : (newStones[stoneA] = count);
+        newStones[stoneB]
+          ? (newStones[stoneB] += count)
+          : (newStones[stoneB] = count);
+      } else if (stone !== "0") {
+        let newStone = (toNum(stone) * 2024).toString();
+        newStones[newStone]
+          ? (newStones[newStone] += count)
+          : (newStones[newStone] = count);
+      }
+    });
+    stones = newStones;
+  }
+  return stones;
+};
+
+let timer = now.instant();
+console.log(
+  "part one:",
+  Object.values(iterate(stones, 25)).reduce((total, curr) => total + curr, 0),
+  printTime(now.instant().since(timer))
+);
+
+timer = now.instant();
+console.log(
+  "part two:",
+  Object.values(iterate(stones, 75)).reduce((total, curr) => total + curr, 0),
+  printTime(now.instant().since(timer))
+);