feat: day 13 claw contraption 1/2 soln, #19

Author: weaponsforge

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

@@ -13,7 +13,7 @@ const input = readAOCInputFile({
  * Part 1/2 of the 2024-12-12 quiz
  * Counts the total fencing price: area * perimeter per plot
  */
-const quiz20241231_01 = () => {
+const quiz20241212_01 = () => {
   const garden = new Garden()
   const totalPrice = garden.calculateFencePrice(input, true)
 
@@ -24,12 +24,12 @@ const quiz20241231_01 = () => {
  * Part 2/2 of the 2024-12-12 quiz
  * Counts the wholesale fencing price: area * perimeter of whole region (edges)
  */
-const quiz20241231_02 = () => {
+const quiz20241212_02 = () => {
   const garden = new WholesaleGarden()
   const totalPrice = garden.calculateFencePrice(input, true)
 
   console.log('---Wholesale fencing price', totalPrice)
 }
 
-quiz20241231_01()
-quiz20241231_02()
+quiz20241212_01()
+quiz20241212_02()

src/2024/2024-12-13/README.md

@@ -0,0 +1,28 @@
+## Day 13: Claw Contraption
+
+Visit the Advent of Code website for more information on this puzzle at:
+
+**Source:** https://adventofcode.com/2024/day/13<br>
+**Status:** On-going ⭐
+
+## Code
+
+### `count.ts`
+
+- **`countTokensPrizes()`** - Counts the minimum number of tokens needed to win all possible prizes.
+
+### `utils.ts`
+
+- **`getDeterminant()`** - Counts the determinant of a 2x2 coefficient matrix. Currently only works with a 2x2 number matrix.
+- **`coefficientMatrix()`** - Builds a coefficient matrix by replacing column values with the constants. Currently only works with a 2x2 number matrix.
+- **`solveEquation()`** - Calculates the number of needed (x,y) button A "and" B presses to reach the prize by solving the 2 equations using Cramer's Rule.
+
+### `fileReader.ts`
+
+- Reads and formats the quiz input TXT file
+
+## References
+
+<sup>[[1]](https://www.youtube.com/watch?v=jBsC34PxzoM)</sup>&nbsp; Cramer's Rule<br>
+<sup>[[2]](https://www.youtube.com/playlist?list=PLybg94GvOJ9En46TNCXL2n6SiqRc_iMB8)</sup>&nbsp; Linear Algebra Videos
+

src/2024/2024-12-13/input.txt

@@ -0,0 +1,15 @@
+Button A: X+94, Y+34
+Button B: X+22, Y+67
+Prize: X=8400, Y=5400
+
+Button A: X+3, Y+8
+Button B: X+4, Y+15
+Prize: X=123, Y=456
+
+Button A: X+17, Y+86
+Button B: X+84, Y+37
+Prize: X=7870, Y=6450
+
+Button A: X+30, Y+9
+Button B: X+78, Y+14
+Prize: X=777, Y=14344

src/2024/2024-12-13/lib/count.ts

@@ -0,0 +1,35 @@
+import type { MatrixData, StepsTokens } from './types.js'
+import { solveEquation } from './utils.js'
+
+/**
+ * Counts the minimum number of tokens needed to win all possible prizes.
+ * @param {MatrixData<number[]>} data - Processed quiz data object containing 2D number matrices
+ * @param {boolean} log - Flag to print the log messages to screen
+ * @returns {StepsTokens} Object containing the number of tokens and prizes
+ */
+export const countTokensPrizes = (
+  data: MatrixData<number[]>,
+  log: boolean = false
+): StepsTokens => {
+  let countPrizes = 0
+  let countTokens = 0
+
+  for (const key in data) {
+    const { x, y } = solveEquation(data[key] as number[][])
+    if (!Number.isInteger(x) || !Number.isInteger(y)) continue
+
+    const tokensA = x * 3
+    const tokensB = y * 1
+    countPrizes += 1
+    countTokens += tokensA + tokensB
+
+    if (log) {
+      console.log(`Machine [${key}], Button A: ${x}, Button B: ${y}, TOTAL`, (tokensA + tokensB))
+    }
+  }
+
+  return {
+    prizes: countPrizes,
+    tokens: countTokens
+  }
+}

src/2024/2024-12-13/lib/fileReader.ts

@@ -0,0 +1,39 @@
+import type { MatrixData } from './types.js'
+
+import { AOC_OUTPUT_TYPE, readAOCInputFile } from '@/aoc/file/aocfile.js'
+import { file } from '@/aoc/file/utils.js'
+
+/**
+ * Reads and formats the quiz input data.
+ * @param {string} fileName - Input file name or relative path
+ * @returns {MatrixData} Object containing 2D number matrices
+ */
+export const fileReader = (fileName: string): MatrixData<number[]> => {
+  const input = readAOCInputFile({
+    filePath: file(import.meta.url, fileName),
+    type: AOC_OUTPUT_TYPE.STRING
+  }) as string
+
+  return input
+    .split('\n\n')
+    .reduce((list: MatrixData<number[]>, block, id) => {
+      const row = block.split('\n')
+      const eq1: number[] = []
+      const eq2: number[]  = []
+
+      row.forEach((item, index) => {
+        const sign = index === row.length - 1 ? '=' : '+'
+        const xIndex = item.indexOf(`X${sign}`)
+        const yIndex = item.indexOf(`Y${sign}`)
+
+        const x = item.substring(xIndex + 2, item.indexOf(','))
+        const y = item.substring(yIndex + 2, item.length)
+
+        eq1.push(Number(x))
+        eq2.push(Number(y))
+      })
+
+      list[id] = [eq1, eq2]
+      return list
+    }, {})
+}

src/2024/2024-12-13/lib/types.ts

@@ -0,0 +1,15 @@
+
+/**
+ * @type {Record<number, T[]>} MatrixData
+ */
+export type MatrixData<T> = Record<number, T[]>
+
+/**
+ * @type {Object} StepsTokens
+ * @property {number} prizes - Number of prizes to win
+ * @property {number} tokens - Minimum number of tokens to move the A/B buttons
+ */
+export type StepsTokens = {
+  prizes: number;
+  tokens: number;
+}

src/2024/2024-12-13/lib/utils.ts

@@ -0,0 +1,63 @@
+import type { Point } from '@/aoc/point/types.js'
+
+/**
+ * Counts the determinant of a 2x2 coefficient matrix. Currently only works with a 2x2 number matrix.
+ * TO-DO: Support N-size matrices.
+ * @param {number[][]} matrix - 2D number matrix input
+ * @returns {number} Determinant of a 2x2 matrix
+ */
+export const getDeterminant = (matrix: number[][]): number => {
+  const eq1 = matrix[0] as number[]
+  const eq2 = matrix[1] as number[]
+
+  return ((eq1[0] as number) * (eq2[1] as number)) -
+    ((eq1[1] as number) * (eq2[0] as number))
+}
+
+/**
+ * Builds a coefficient matrix by replacing column values with the constants.
+ * Currently only works with a 2x2 number matrix. TO-DO: Support N-size matrices.
+ * @param {number[][]} matrix - 2D number matrix input
+ * @param {number} column - Matrix column index to replace with constants. Index starts at `0`.
+ * @returns {number[][]} Coefficient matrix
+ */
+export const coefficientMatrix = (
+  matrix: number[][],
+  column: number = 0
+): number[][] => {
+  const maxCol = 2
+
+  return matrix.reduce((list: number[][], row, y) => {
+    const items = row.reduce((sublist: number[], item, x) => {
+      if (x === column) {
+        sublist.push(matrix[y]![maxCol] as number)
+      } else if (x !== maxCol) {
+        sublist.push(item)
+      }
+      return sublist
+    }, [])
+    return [...list, items]
+  }, [])
+}
+
+/**
+ * Calculates the number of needed (x,y) button A "and" B presses to reach the prize
+ * by solving the 2 equations using Cramer's Rule.
+ * https://www.youtube.com/watch?v=RdLo-9jh2EM. Currently only works with a 2x2 number matrix.
+ * @param {number[][]} matrix - 2D number matrix input
+ * @returns {Point} Object containing the number of `x` and `y` button presses
+ */
+export const solveEquation = (matrix: number[][]): Point => {
+  const determinant = getDeterminant(matrix)
+
+  const xCoefficient = coefficientMatrix(matrix, 0)
+  const yCoefficient = coefficientMatrix(matrix, 1)
+
+  const xD = getDeterminant(xCoefficient)
+  const yD = getDeterminant(yCoefficient)
+
+  const x = xD / determinant
+  const y = yD / determinant
+
+  return { x, y }
+}

src/2024/2024-12-13/main.ts

@@ -0,0 +1,17 @@
+import { fileReader } from './lib/fileReader.js'
+import { countTokensPrizes } from './lib/count.js'
+
+const data = fileReader('../input.txt')
+
+/**
+ * Part 1/2 of the 2024-12-14 quiz
+ * Counts the minimum number of tokens needed to win all possible prizes.
+ */
+const quiz20241213_01 = () => {
+  const { prizes, tokens } = countTokensPrizes(data, true)
+
+  console.log('All prizes', prizes)
+  console.log('Minimum tokens', tokens)
+}
+
+quiz20241213_01()

src/2024/2024-12-13/sample.test.ts

@@ -0,0 +1,11 @@
+import { test, expect } from 'vitest'
+
+import { fileReader } from './lib/fileReader.js'
+import { countTokensPrizes } from './lib/count.js'
+
+const data = fileReader('../input.txt')
+
+test('Number of tokens and prizes', () => {
+  expect(countTokensPrizes(data).prizes).toBe(2)
+  expect(countTokensPrizes(data).tokens).toBe(480)
+})

src/aoc/grid/utils.ts

@@ -67,7 +67,7 @@ export const isOutOfBounds = (point: Point, gridMeta: GridDimensions): boolean =
 
 /**
  * Retrieves the four (4) diagonally aligned (y,x) coordinates and the symbol character from a `Point` in the grid.
- * Substitutes a `"*"` symbol character in the `PointSymbol.symbol`if the `point` is out of the grid bounds.
+ * Substitutes a `"*"` symbol character in the `PointSymbol.symbol` to coordinates out of the grid bounds.
  * @param {Point} point - (y,x) coordinate object in a 2D array grid
  * @param {string[][]} data - 2D string array input
  * @returns {PointSymbol[]} Array of `PointSymbol` with symbol characters.
@@ -96,7 +96,7 @@ export const getDiagonalNeighbors = (point: Point, data: string[][]): PointSymbo
 
 /**
  * Retrieves the four (4) horizontal/vertical aligned (y,x) coordinates and the symbol character from a `Point` in the grid.
- * Substitutes a `"*"` symbol character in the `PointSymbol.symbol`if the `point` is out of the grid bounds.
+ * Substitutes a `"*"` symbol character in the `PointSymbol.symbol` to coordinates out of the grid bounds.
  * @param {Point} point - (y,x) coordinate object in a 2D array grid
  * @param {string[][]} data - 2D string array input
  * @returns {PointSymbol[]} Array of `PointSymbol` with symbol characters.