From 3c9b48b3a68264a1c16e7d8d99600f70f489beb0 Mon Sep 17 00:00:00 2001
From: Pascal Syma <pascal@syma.dev>
Date: Wed, 11 Dec 2024 15:30:15 +0100
Subject: [PATCH] Solve 2024-11

---
 2024/11/2024-11.run.xml |  7 ++++
 2024/11/index.test.ts   | 19 +++++++++++
 2024/11/index.ts        | 73 +++++++++++++++++++++++++++++++++++++++++
 2024/11/run.ts          | 12 +++++++
 4 files changed, 111 insertions(+)
 create mode 100644 2024/11/2024-11.run.xml
 create mode 100644 2024/11/index.test.ts
 create mode 100644 2024/11/index.ts
 create mode 100644 2024/11/run.ts

diff --git a/2024/11/2024-11.run.xml b/2024/11/2024-11.run.xml
new file mode 100644
index 0000000..7a6d177
--- /dev/null
+++ b/2024/11/2024-11.run.xml
@@ -0,0 +1,7 @@
+<component name="ProjectRunConfigurationManager">
+  <configuration default="false" name="2024-11" type="BunRunConfiguration">
+    <option name="program" value="2024/11/run.ts" />
+    <option name="workingDirectory" value="$PROJECT_DIR$" />
+    <method v="2" />
+  </configuration>
+</component>
\ No newline at end of file
diff --git a/2024/11/index.test.ts b/2024/11/index.test.ts
new file mode 100644
index 0000000..11571ba
--- /dev/null
+++ b/2024/11/index.test.ts
@@ -0,0 +1,19 @@
+import { describe, expect, it } from 'bun:test';
+import { solve, solveFirstSlow } from './index.ts';
+
+describe('2024-11', () => {
+  const testInput = `125 17`;
+  it('first slow', () => {
+    // it takes too long
+    // so only run while `NODE_ENV=production bun test --coverage`
+    if (process.env.NODE_ENV === 'production') {
+      expect(solveFirstSlow(testInput)).toBe(55312);
+    }
+  });
+  it('first', () => {
+    expect(solve(testInput, 25)).toBe(55312);
+  });
+  it('second', () => {
+    expect(solve(testInput, 75)).toBeGreaterThan(55312);
+  });
+});
diff --git a/2024/11/index.ts b/2024/11/index.ts
new file mode 100644
index 0000000..2a2a1e4
--- /dev/null
+++ b/2024/11/index.ts
@@ -0,0 +1,73 @@
+import { sumArray } from '../../utils/array.ts';
+import { MultiMap } from '../../utils/multi-map.ts';
+
+export function solveFirstSlow(input: string): number {
+  const stones = input.split(' ');
+
+  for (let i = 0; i < 25; i++) {
+    let j = 0;
+    while (j < stones.length) {
+      const stone = stones[j];
+      if (stone === '0') {
+        stones[j] = '1';
+        j++;
+        continue;
+      }
+      if (stone.length % 2 === 0) {
+        const secondStone = stone.substring(stone.length / 2);
+        stones.splice(j + 1, 0, String(Number(secondStone)));
+        stones[j] = stone.substring(0, stone.length / 2);
+        j += 2;
+        continue;
+      }
+
+      stones[j] = String(Number(stone) * 2024);
+      j++;
+    }
+  }
+
+  return stones.length;
+}
+
+const lookup = new MultiMap<number, [number, string]>();
+
+function splits(stone: string, times: number): number {
+  const lookedUp = lookup.multiGet(times, stone);
+  if (lookedUp !== undefined) {
+    return lookedUp;
+  }
+
+  if (times <= 0) {
+    const result = 1;
+    lookup.multiSet(result, times, stone);
+    return result;
+  }
+  if (stone === '0') {
+    const result = splits('1', times - 1);
+    lookup.multiSet(result, times, stone);
+    return result;
+  }
+  if (stone.length % 2 === 0) {
+    const secondStone = stone.substring(stone.length / 2);
+    const firstStone = stone.substring(0, stone.length / 2);
+    const result =
+      splits(firstStone, times - 1) +
+      splits(String(Number(secondStone)), times - 1);
+
+    lookup.multiSet(result, times, stone);
+    return result;
+  }
+
+  const result = splits(String(Number(stone) * 2024), times - 1);
+
+  lookup.multiSet(result, times, stone);
+  return result;
+}
+
+export function solve(input: string, iterations: number): number {
+  const stones = input.split(' ');
+
+  const count = stones.map((stone) => splits(stone, iterations));
+
+  return sumArray(count);
+}
diff --git a/2024/11/run.ts b/2024/11/run.ts
new file mode 100644
index 0000000..1490124
--- /dev/null
+++ b/2024/11/run.ts
@@ -0,0 +1,12 @@
+import { join } from 'path';
+import { solve } from './index.ts';
+
+const input = await Bun.file(join(__dirname, 'input.txt')).text();
+
+const firstAnswer = solve(input, 25);
+
+console.log(firstAnswer);
+
+const secondAnswer = solve(input, 75);
+
+console.log(secondAnswer);