AoC 2024 - Day 11 (part I solution)

sweko · Dec 11, 2024 · 3d40e6a · 3d40e6a
1 parent bc61ce6
commit 3d40e6a
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Showing 2 changed files with 66 additions and 10 deletions.
diff --git a/2024/ts/day-11/code.ts b/2024/ts/day-11/code.ts
@@ -1,6 +1,6 @@
 // Solution for day 11 of advent of code 2024
 
-import { readInputLines, readInput } from "../system/aoc-helper";
+import { readInputLines, readInput, dlog } from "../system/aoc-helper";
 import "../utils/array-helpers";
 import { Puzzle } from "../model/puzzle";
 
@@ -11,41 +11,97 @@ const processInput = (day: number) => {
 };
 
 const partOne = (input: number[], debug: boolean) => {
-    const stones = input.slice();
+    let stones = input.slice();
 
     const loopTarget = 25;
 
     for (let loop = 1; loop <= loopTarget; loop++) {
         let index = 0;
+        const nextStones = [];
+
         while (index < stones.length) {
             const stone = stones[index];
             if (stone === 0) {
-                stones[index] = 1;
+                nextStones.push(1);
                 index += 1;
                 continue;
             }
             const stoneStr = stone.toString();
             if (stoneStr.length % 2 === 0) {
                 const firstHalf = parseInt(stoneStr.slice(0, stoneStr.length / 2), 10);
                 const secondHalf = parseInt(stoneStr.slice(stoneStr.length / 2), 10);
-                stones[index] = firstHalf;
-                stones.splice(index + 1, 0, secondHalf);
-                index += 2;
+                nextStones.push(firstHalf);
+                nextStones.push(secondHalf);
+                index += 1;
                 continue;
             }
 
-            stones[index] = stones[index] * 2024;
+            nextStones.push(stones[index] * 2024);
             index += 1;
         }
-        //console.log(`Loop ${loop} - ${stones}`);
+        stones = nextStones;
+        dlog(`Loop ${loop} - ${stones}`);
     }
     return stones.length;
 };
 
+type LinkedList = {
+    value: number;
+    next: LinkedList | null;
+}
+
+const toLinkedList = (input: number[]): LinkedList => {
+    let head: LinkedList = { value: input[0], next: null };
+    let current = head;
+    for (let index = 1; index < input.length; index++) {
+        current.next = { value: input[index], next: null };
+        current = current.next;
+    }
+    return head;
+}
+
+const partOneLinkedList = (input: number[], debug: boolean) => {
+    let stones = input.slice();
+
+    const head = toLinkedList(stones);
+    let count = stones.length;
+
+    const loopTarget = 25;
+
+    for (let loop = 1; loop <= loopTarget; loop++) {
+        let current: LinkedList | null = head;
+
+        while (current !== null) {
+            if (current.value === 0) {
+                current.value = 1;
+                current = current.next;
+                continue;
+            }
+            const stoneStr = current.value.toString();
+            if (stoneStr.length % 2 === 0) {
+                const firstHalf = parseInt(stoneStr.slice(0, stoneStr.length / 2), 10);
+                const secondHalf = parseInt(stoneStr.slice(stoneStr.length / 2), 10);
+                current.value = firstHalf;
+                const newStone = { value: secondHalf, next: current.next };
+                current.next = newStone;
+                current = newStone.next;
+                count += 1;
+                continue;
+            }
+
+            current.value = current.value * 2024;
+            current = current.next;
+        }
+
+        dlog(`Loop ${loop} - ${count}`);
+    }
+    return count;
+};
+
 const partTwo = (input: number[], debug: boolean) => {
     let stones = input.slice();
 
-    const loopTarget = 75;
+    const loopTarget = 10;
 
     for (let loop = 1; loop <= loopTarget; loop++) {
         const newStones = [];

diff --git a/2024/ts/day-11/input.txt b/2024/ts/day-11/input.txt
@@ -1 +1 @@
-125 17
+27 10647 103 9 0 5524 4594227 902936