2024 day 11 part 1

Author: pvainio

2024/js/day11.js

@@ -0,0 +1,20 @@
+const stones = '572556 22 0 528 4679021 1 10725 2790'.split(' ').map(s => Number(s));
+
+const blinkStone = (stone) => {
+  if (stone == 0) return [1];
+  const str = `${stone}`;
+  if (str.length % 2 == 0) {
+    const middle = str.length / 2;
+    const [left, right] = [str.substring(0, middle), str.substring(middle)];
+    return [Number(left), Number(right)];
+  }
+  return [2024 * stone];
+};
+
+const blink = (stones) => stones.flatMap(s => blinkStone(s));
+
+let afterBlink = stones;
+for (let i = 0; i < 25; i++) {
+  afterBlink = blink(afterBlink);
+}
+console.log(afterBlink.length);