feat: day 11 plutonian pebbles 20241211

README.md

@@ -19,6 +19,7 @@ The codes are structured in a way that discusses and walks through the solution
 - Day 8: Resonant Collinearity [[link]](/src/2024/2024-12-08/README.md)
 - Day 9: Disk Fragmenter [[link]](/src/2024/2024-12-09/README.md)
 - Day 10: Hoof It [[link]](/src/2024/2024-12-10/README.md)
+- Day 11: Plutonian Pebbles [[link]](/src/2024/2024-12-11/README.md)
 
 </details>
 

src/2024/2024-12-11/README.md

@@ -0,0 +1,20 @@
+## Day 11: Plutonian Pebbles
+
+Visit the Advent of Code website for more information on this puzzle at:
+
+**Source:** https://adventofcode.com/2024/day/11<br>
+**Status:** Complete ⭐⭐
+
+## Code
+
+### `utils.ts` - contains helper and utility scripts for the quiz.
+
+- `isEvenDigits()` - Checks if a number has an even number of digits
+- `halfDigit()` - Divides the number into two (2) separate groups (digits) if they have an even number of digits, each group having half the original number's digits.
+- `arrayToObject()` - Converts an array of numbers to an Object, using the array number elements as keys with a default numeric value of `1`
+
+### `blink.ts`
+
+- **`Blinker`** class
+   - A class that counts the number of transformed and new stones after blinking.
+   - Has methods for storing the stone's data, counting, and "blinking."

src/2024/2024-12-11/lib/blink.ts

@@ -0,0 +1,68 @@
+import { arrayToObject, isEvenDigits, halfDigit } from './utils.js'
+
+/**
+ * @class Blinker
+ * @description A class that counts the number of transformed and new stones after blinking.
+ */
+export class Blinker {
+  /** Stone numbers tracking storage at each blink */
+  numberStorage: Record<number, number> = {}
+
+  /** Total number of stones after the last blink */
+  stoneCount: number = 0
+
+  /**
+   * Stores a number in the `this.numberStorage` object as a key with value.
+   * @param {number} stoneNum - Number to store in an Object data
+   * @param {number} value - Number value associated with the `stoneNum` number key
+   * @returns {void}
+   */
+  store (stoneNum: number, value: number = 1): void {
+    if (this.numberStorage[stoneNum] === undefined) {
+      this.numberStorage[stoneNum] = value
+    } else {
+      this.numberStorage[stoneNum] += value
+    }
+  }
+
+  /**
+   * Simulates the quiz's "blink" and stones morphing.
+   * Calculates the number of transformed stones after blinking `blinkTimes`
+   * @param {number[]} stones - Array of numbers (stones)
+   * @param {number} blinkTimes - Number of times to simulate "blinking"
+   * @returns {number} Total number of transformed stones after blinking
+   */
+  blink (stones: number[], blinkTimes: number): number {
+    let unique = arrayToObject([...stones])
+
+    for (let i = 0; i < blinkTimes; i += 1) {
+      for (const num in unique) {
+        const numberKey = Number(num)
+        const count = unique[numberKey] as number
+
+        if (numberKey === 0) {
+          this.store(1, count)
+        } else if (isEvenDigits(numberKey)) {
+          const group = halfDigit(numberKey)
+
+          group.forEach(part => {
+            this.store(part, count)
+          })
+        } else {
+          this.store(numberKey * 2024, count)
+        }
+      }
+
+      unique = { ...this.numberStorage }
+      this.numberStorage = {}
+
+      this.stoneCount = Object
+        .values(unique)
+        .reduce(
+          (sum, ct) => sum += ct, 0
+        )
+    }
+
+    return this.stoneCount
+  }
+}

src/2024/2024-12-11/lib/utils.ts

@@ -0,0 +1,37 @@
+/**
+ * Checks if a number has an even number of digits
+ * @param {number} number - Number input
+ */
+export const isEvenDigits = (number: number): boolean => {
+  return number.toString().length % 2 === 0
+}
+
+/**
+ * Divides the number into two (2) separate groups (digits) if they have an even number of digits,
+ * aach group having half the original number's digits.
+ * @param {number} number - Number input
+ */
+export const halfDigit = (number: number): number[] => {
+  const numberStr = number.toString()
+
+  return [
+    Number(numberStr.substring(0, numberStr.length / 2)),
+    Number(numberStr.substring(
+      numberStr.length / 2, numberStr.length)
+    )
+  ]
+}
+
+/**
+ * Converts an array of numbers to an Object, using the array number elements as keys with a default numeric value of `1`
+ * @param {number[]} numbers - Array of numbers
+ * @returns {Record<number, number>} Object
+ */
+export const arrayToObject = (numbers: number[]): Record<number, number> => {
+  return numbers.reduce((list: Record<number, number>, num) =>
+    (list[num] === undefined
+      ? list[num] = 1
+      : list[num] += 1, list),
+  {}
+  )
+}

src/2024/2024-12-11/main.ts

@@ -0,0 +1,17 @@
+import { Blinker } from './lib/blink.js'
+
+/**
+ * Part 1/2 and 2/2 of the 2024-12-10 quiz
+ * Counts the number of visible stones after blinking
+ */
+const quiz20241211 = () => {
+  const numBlinks = 25
+  const blinker = new Blinker()
+
+  const stones = '125 17'.split(' ').map(Number)
+  const count = blinker.blink(stones, numBlinks)
+
+  console.log(`${count} stones available after ${numBlinks} blinks`)
+}
+
+quiz20241211()

src/2024/2024-12-11/sample.test.ts

@@ -0,0 +1,9 @@
+import { test, expect } from 'vitest'
+import { Blinker } from './lib/blink.js'
+
+test('Number of stones after blinking:', () => {
+  const stones = '125 17'.split(' ').map(Number)
+  const blinker = new Blinker()
+
+  expect(blinker.blink(stones, 25)).toBe(55312)
+})