Add solution day 11

day_11/input.txt

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+6 11 33023 4134 564 0 8922422 688775

day_11/solve_1.ts

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+export async function readInputData(path: string): Promise<number[]> {
+    const data = await Deno.readTextFile(path);
+    return data.trim().split(" ").map((x) => parseInt(x));
+}
+
+export function step(k: number): [number, number] | number {
+    if (k === 0) return 1;
+    const str = k.toString();
+    if (str.length % 2 === 0) {
+        return [
+            parseInt(str.slice(0, str.length / 2)),
+            parseInt(str.slice(str.length / 2)),
+        ];
+    }
+    return k * 2024;
+}
+
+if (import.meta.main) {
+    const input = await readInputData("input.txt");
+    console.log(input);
+    let data = input;
+    for (let i = 0; i < 25; i++) {
+        data = data.flatMap(step);
+    }
+    console.log(data.length);
+    // let input = [125, 17]
+    // for (let i = 0; i < 6; i++) {
+    //     input = input.flatMap(step);
+    //     console.log(input);
+    // }
+}

day_11/solve_2.ts

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+import { readInputData, step as stepNext } from "./solve_1.ts";
+
+let memo: Map<string, number> = new Map();
+function countStone(start: number, step: number): number {
+    if (step === 0) return 1;
+    const key = `${start},${step}`;
+    const memoized = memo.get(key);
+    if (memoized) return memoized;
+    const next = stepNext(start);
+    if (typeof next === "number") {
+        const count = countStone(next, step - 1);
+        memo.set(key, count);
+        return count;
+    }
+    const [a, b] = next;
+    const count = countStone(a, step - 1) + countStone(b, step - 1);
+    memo.set(key, count);
+    return count;
+}
+
+if (import.meta.main) {
+    const input = await readInputData("input.txt");
+    const data = input;
+    console.log(data.reduce((a, b) => a + countStone(b, 75), 0));
+    // let input = [125, 17]
+    // for (let i = 0; i < 6; i++) {
+    //     input = input.flatMap(step);
+    //     console.log(input);
+    // }
+}