feat(2021-day-04): find the last board that will score a bingo

Author: developher-net

2021/day-04/bingo.js

@@ -1,15 +1,3 @@
-const boards = []
-
-const callNumber = (called) => {
-  for (let x = 0; x < boards.length; x++) {
-    markBoard(x, called)
-    if (checkWinner(x) === 'winner') {
-      console.debug(`Board ${x} is the winner`)
-      return x
-    }
-  }
-}
-
 const markBoard = (board, called) => {
   for (let x = 0; x < 5; x++) {
     for (let y = 0; y < 5; y++) {
@@ -69,7 +57,6 @@ const scoreBoard = (board) => {
 }
 
 module.exports = {
-  callNumber,
   scoreBoard,
   checkWinner,
   markBoard

2021/day-04/bingo.test.js

@@ -1,7 +1,7 @@
 /* eslint-env mocha */
 const { expect } = require('chai')
-const { callNumber, scoreBoard, checkWinner, markBoard } = require('./bingo')
-const { parseData } = require('../../2018/inputParser')
+const { scoreBoard, checkWinner, markBoard } = require('./bingo')
+const { parseData, linesToArray } = require('../../2018/inputParser')
 
 const testData = `
 7,4,9,5,11,17,23,2,0,14,21,24,10,16,13,6,15,25,12,22,18,20,8,19,3,26,1
@@ -25,10 +25,11 @@ const testData = `
  2  0 12  3  7
 `
 // Deep copy to ensure we aren't mutating the original data
-const data = JSON.parse(JSON.stringify(testData))
+const data = JSON.parse(JSON.stringify(linesToArray(testData)))
 
 // split up data
 const testDraws = parseData(data.shift())
+console.debug(testDraws)
 const testBoards = []
 for (let x = 0; x < data.length; x = x + 5) {
   testBoards.push(
@@ -56,34 +57,6 @@ describe('--- Day 4: Giant Squid ---', () => {
         ]
         expect(markBoard(board, 5)).to.deep.equal(expected)
       })
-      it.skip('can be used in a loop to find', () => {
-        // callNumber(7)
-        // callNumber(4)
-        // callNumber(9)
-        // callNumber(5)
-        // callNumber(11)
-        // for(var x = 0; x < testBoards)
-        // expect(boards[0]).to.deep.equal(board0)
-        // expect(boards[1]).to.deep.equal(board1)
-        // expect(boards[2]).to.deep.equal(board2)
-        // callNumber(17)
-        // callNumber(23)
-        // callNumber(2)
-        // callNumber(0)
-        // callNumber(14)
-        // callNumber(21)
-        // expect(boards[0]).to.deep.equal(board0)
-        // expect(boards[1]).to.deep.equal(board1)
-        // expect(boards[2]).to.deep.equal(board2)
-      })
-      it.skip('identifies the winner', () => {
-        expect(callNumber(24)).to.equal(3)
-      })
-    })
-    describe('findWinner()', () => {
-      it.skip('loops through the boards and checks for a winner', () => {
-
-      })
     })
     describe('checkWinner()', () => {
       it('checks to see if a board has a horizontal bingo', () => {

2021/day-04/solution.js

@@ -59,9 +59,37 @@ fs.readFile(filePath, { encoding: 'utf8' }, (err, initData) => {
   }
 
   const part2 = () => {
-    // const data = resetInput()
-    // console.debug(data)
-    return 'No answer yet'
+    const data = resetInput()
+
+    let draw = -1
+    let lastWin = []
+    let lastDraw = 0
+
+    while (data.boards.length >= 1 && draw < data.draws.length) {
+      // next draw
+      draw++
+
+      // Mark each board that has the number
+      console.debug(`Checking draw ${data.draws[draw]}`)
+      data.boards = data.boards.map((board) => {
+        return markBoard(board, data.draws[draw])
+      })
+
+      // Filter out any winners
+      data.boards = data.boards.filter((board) => {
+        if (checkWinner(board) === 'winner') {
+          lastWin = board
+          lastDraw = data.draws[draw]
+          return false
+        } else {
+          return true
+        }
+      })
+    }
+
+    // last winner found
+    console.debug(`Score is ${scoreBoard(lastWin)} on draw ${lastDraw}`)
+    return scoreBoard(lastWin) * lastDraw
   }
   const answers = []
   answers.push(part1())