From 6eff31e69c772ad87bae930bc5161da2f597ae66 Mon Sep 17 00:00:00 2001
From: "NullDev (Shadow)" <chris@nulldev.org>
Date: Wed, 11 Dec 2024 06:39:01 +0100
Subject: [PATCH] Day 11 part 2

---
 2024/Day_11/part_2.js | 23 +++++++++++++++++------
 README.md             |  1 +
 2 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/2024/Day_11/part_2.js b/2024/Day_11/part_2.js
index 6376d62..2150883 100644
--- a/2024/Day_11/part_2.js
+++ b/2024/Day_11/part_2.js
@@ -8,16 +8,27 @@ const __dirname = path.dirname(fileURLToPath(import.meta.url));
 // = Copyright (c) NullDev = //
 // ========================= //
 
-const INPUT = String(fs.readFileSync(path.join(__dirname, "input.txt"))).trim().split("\n");
+/* eslint-disable no-nested-ternary */
+
+const INPUT = String(fs.readFileSync(path.join(__dirname, "input.txt"))).trim().split(" ").map(Number);
 
 const pStart = performance.now();
 
-//
-// YOUR CODE HERE
-//
-const result = "...";
+const mem = {};
+const run = (
+    s, steps, key = `${s}|${steps}`,
+) => ((steps === 0) ? 1 : ((key in mem)
+    ? mem[key]
+    : (mem[key] = (s === 0)
+        ? run(1, steps - 1)
+        : (String(s).length % 2 === 0)
+            ? run(Number(String(s).substring(0, String(s).length / 2)), steps - 1)
+                + run(Number(String(s).substring(String(s).length / 2)), steps - 1)
+            : run(s * 2024, steps - 1)), mem[key]));
+
+const res = INPUT.map(s => run(s, 75)).reduce((acc, x) => acc + x);
 
 const pEnd = performance.now();
 
-console.log("<DESCRIPTION>: " + result);
+console.log("STONES AFTER BLINKING 75 TIMES: " + res);
 console.log(pEnd - pStart);
diff --git a/README.md b/README.md
index 902e9b7..f2e8e24 100644
--- a/README.md
+++ b/README.md
@@ -133,6 +133,7 @@ I also tried to experiment with a couple of different things:
 - [DFS](https://en.wikipedia.org/wiki/Depth-first_search) with Memoization in [Day_07/part_2.js](https://github.com/NullDev/Advent-of-Code/blob/master/2024/Day_07/part_2.js)
 - One-Liner in both [Day_08/part_1.js](https://github.com/NullDev/Advent-of-Code/blob/master/2024/Day_08/part_1.js) and [Day_08/part_2.js](https://github.com/NullDev/Advent-of-Code/blob/master/2024/Day_08/part_2.js)
 - _Almost_ One-Liner [DFS](https://en.wikipedia.org/wiki/Depth-first_search) in both [Day_10/part_1.js](https://github.com/NullDev/Advent-of-Code/blob/master/2024/Day_10/part_1.js) and [Day_10/part_2.js](https://github.com/NullDev/Advent-of-Code/blob/master/2024/Day_10/part_2.js)
+- Recursive memoized _almost_ One-Liner in [Day_11/part_1.js](https://github.com/NullDev/Advent-of-Code/blob/master/2024/Day_11/part_1.js) and [Day_11/part_2.js](https://github.com/NullDev/Advent-of-Code/blob/master/2024/Day_11/part_2.js)
 
 <hr>