From 2960b89991f1b1ef3535b9f498836f992ee83752 Mon Sep 17 00:00:00 2001
From: Wiktoria Van Harneveldt <w.dev+git@mailbox.org>
Date: Wed, 11 Dec 2024 20:44:22 +0100
Subject: [PATCH] d11 p2

---
 src/11.ts       | 38 +++++++++++++++++++++++++++++++++++++-
 test/11.test.ts |  2 +-
 2 files changed, 38 insertions(+), 2 deletions(-)

diff --git a/src/11.ts b/src/11.ts
index 97b84d0..f1895ca 100644
--- a/src/11.ts
+++ b/src/11.ts
@@ -4,6 +4,7 @@ function solution(input: string): { part1: string; part2: string } {
 
   const lines = input.split(" ");
   const totalBlinkAmount = 25;
+  const totalBlinkAmount2 = 75;
   let stones: string[] = [...lines];
 
   for (let i = 0; i < totalBlinkAmount; i++) {
@@ -20,9 +21,44 @@ function solution(input: string): { part1: string; part2: string } {
       return (Number(line) * 2024).toString();
     });
   }
-
   result1 = stones.length;
 
+  const cache = new Map<string, number>();
+
+  function ans(stone: number, iter: number): number {
+    if (iter === 0) {
+      return 1;
+    }
+
+    if (cache.has(`${stone},${iter}`)) {
+      return cache.get(`${stone},${iter}`)!;
+    }
+
+    let res = 0;
+
+    if (stone === 0) {
+      res = ans(1, iter - 1);
+    } else if (stone.toString().length % 2 === 0) {
+      const st = stone.toString();
+      const half = st.length / 2;
+      const firstHalf = st.slice(0, half);
+      const secondHalf = st.slice(half);
+
+      res = 0;
+      res += ans(Number(firstHalf), iter - 1);
+      res += ans(Number(secondHalf), iter - 1);
+    } else {
+      res = ans(stone * 2024, iter - 1);
+    }
+    cache.set(`${stone},${iter}`, res);
+
+    return cache.get(`${stone},${iter}`)!;
+  }
+
+  lines.map(Number).forEach((line) => {
+    result2 += ans(line, totalBlinkAmount2);
+  });
+
   return {
     part1: result1.toString(),
     part2: result2.toString(),
diff --git a/test/11.test.ts b/test/11.test.ts
index 3df0d22..edd65ce 100644
--- a/test/11.test.ts
+++ b/test/11.test.ts
@@ -5,7 +5,7 @@ const EXAMPLE_1 = `125 17`;
 const RESULT_1 = "55312";
 
 const EXAMPLE_2 = EXAMPLE_1;
-const RESULT_2 = "31";
+const RESULT_2 = "65601038650482";
 
 describe("Day 11", () => {
   test("Part 1", () => {