day 11

src/day11/README.md

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+# 🎄 Advent of Code 2024 - day 11 🎄
+
+## Info
+
+Task description: [link](https://adventofcode.com/2024/day/11)
+
+## Notes
+
+...

src/day11/index.ts

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+import run from "aocrunner"
+
+const parseInput = (rawInput: string) => rawInput.split(' ').map(Number)
+
+function cacheKey(...args) { // good enough
+  return args.map(String).join('\n');
+}
+function memoize<T extends unknown[],U>(fn: (...args: T) => U): (...args: T) => U {
+  const cache = {}; // Saves the values
+  return (...args) => {
+    const key = cacheKey(...args);
+    if (!cache[key]) { // Not in the cache? Call fn.
+      cache[key] = fn(...args); // Now it's in the cache.
+    }
+    return cache[key];
+  }
+}
+
+const part1 = (rawInput: string) => {
+  const input = parseInput(rawInput)
+  const blink = (n: number, turn: number): number[] => {
+    if (turn === 0) return [n]
+    if (n === 0) return blink(1, turn - 1)
+    const digits = Math.floor(Math.log10(n)) + 1
+    if (digits % 2 === 0) {
+      const exp = 10**(digits/2)
+      return [
+        ...blink(Math.floor(n / exp), turn - 1),
+        ...blink(n % exp, turn - 1)
+      ]
+    }
+    return blink(n * 2024, turn - 1)
+  }
+  return input.flatMap(s => blink(s, 25)).length
+}
+
+const part2 = (rawInput: string) => {
+  const input = parseInput(rawInput)
+  const count = memoize((n: number, turn: number): number => {
+    if (turn === 0) return 1
+    if (n === 0) return count(1, turn - 1)
+    const digits = Math.floor(Math.log10(n)) + 1
+    if (digits % 2 === 0) {
+      const exp = 10**(digits/2)
+      return count(Math.floor(n / exp), turn - 1) + count(n % exp, turn - 1)
+    }
+    return count(n * 2024, turn - 1)
+  })
+  return input.reduce((total, s) => total + count(s, 75), 0)
+}
+
+run({
+  part1: {
+    tests: [
+      // {
+      //   input: ``,
+      //   expected: "",
+      // },
+    ],
+    solution: part1,
+  },
+  part2: {
+    tests: [
+      // {
+      //   input: ``,
+      //   expected: "",
+      // },
+    ],
+    solution: part2,
+  },
+  trimTestInputs: true,
+  onlyTests: false,
+})