Merge pull request #206 from amclin/feat/2021-day-08

Feat/2021 day 08

2021/day-08/display.test.js

@@ -0,0 +1,86 @@
+/* eslint-env mocha */
+const { expect } = require('chai')
+const { descrambleSignal, decodeSignal, parseEntry } = require('./display')
+
+const testSingle = 'acedgfb cdfbe gcdfa fbcad dab cefabd cdfgeb eafb cagedb ab | cdfeb fcadb cdfeb cdbaf'
+
+const testMultiple = `be cfbegad cbdgef fgaecd cgeb fdcge agebfd fecdb fabcd edb | fdgacbe cefdb cefbgd gcbe
+edbfga begcd cbg gc gcadebf fbgde acbgfd abcde gfcbed gfec | fcgedb cgb dgebacf gc
+fgaebd cg bdaec gdafb agbcfd gdcbef bgcad gfac gcb cdgabef | cg cg fdcagb cbg
+fbegcd cbd adcefb dageb afcb bc aefdc ecdab fgdeca fcdbega | efabcd cedba gadfec cb
+aecbfdg fbg gf bafeg dbefa fcge gcbea fcaegb dgceab fcbdga | gecf egdcabf bgf bfgea
+fgeab ca afcebg bdacfeg cfaedg gcfdb baec bfadeg bafgc acf | gebdcfa ecba ca fadegcb
+dbcfg fgd bdegcaf fgec aegbdf ecdfab fbedc dacgb gdcebf gf | cefg dcbef fcge gbcadfe
+bdfegc cbegaf gecbf dfcage bdacg ed bedf ced adcbefg gebcd | ed bcgafe cdgba cbgef
+egadfb cdbfeg cegd fecab cgb gbdefca cg fgcdab egfdb bfceg | gbdfcae bgc cg cgb
+gcafb gcf dcaebfg ecagb gf abcdeg gaef cafbge fdbac fegbdc | fgae cfgab fg bagce`.split('\n')
+
+describe('--- Day 8: Seven Segment Search ---', () => {
+  describe('Part 1', () => {
+    describe('descrambleSignal()', () => {
+      const testData = testSingle.split('|')[0].trim()
+      const { segmentCodes, charCodes } = descrambleSignal(testData)
+
+      it('takes scambled string of 10 codes and identifies the letters matching each seven-digit-display segment', () => {
+        expect(segmentCodes.length).to.equal(7)
+        expect(segmentCodes.filter((code) => !['a', 'b', 'c', 'd', 'e', 'f', 'g'].includes(code)).length).to.equal(0)
+      })
+
+      it('produces a list of character codes for each number that can be displayed', () => {
+        // There should be exactly 10 numbers
+        expect(charCodes.length).to.equal(10)
+        // lengths of each code is predictable as each number has a specific count of segments
+        const expectedLengths = [6, 2, 5, 5, 4, 5, 6, 3, 7, 6]
+        expect(charCodes.map(code => code.length)).to.deep.equal(expectedLengths)
+      })
+    })
+    describe('decodeSignal()', () => {
+      const testData = testMultiple[0].split('|').map((a) => a.trim())
+      const { charCodes } = descrambleSignal(testData[0])
+
+      it('decodes a display pattern using the provided map of display codes', () => {
+        const result = decodeSignal(charCodes, testData[1])
+        expect(result[0]).to.equal(8)
+        expect(result[3]).to.equal(4)
+      })
+      it('throws an error if a digit doesn`t have a matching code', () => {
+        expect(
+          () => decodeSignal(
+            [['a']],
+            'dcb'
+          )
+        ).to.throw(
+          'No match found for dcb when cleaned up to b,c,d'
+        )
+      })
+      it('throws an error if a digit has multiple matches (meaning a bad codes map)', () => {
+        expect(
+          () => decodeSignal(
+            [['a'], ['d', 'c', 'b'], ['b', 'c', 'd']],
+            'dcb'
+          )
+        ).to.throw(
+          'Too many matches for dcb when cleaned up to b,c,d. This most likely indicates a bad list of character codes.'
+        )
+      })
+    })
+  })
+  describe('Part 2', () => {
+    describe('parseEntry()', () => {
+      it('parses a set of scrambled codes and signal to produce a number for display', () => {
+        expect(
+          parseEntry(
+            testSingle.split('|').map((x) => x.trim())
+          )
+        ).to.equal(5353)
+
+        const testData = testMultiple.map(
+          (entry) => entry.split('|')
+            .map((x) => x.trim())
+        ).map(parseEntry)
+
+        expect(testData.reduce((a, b) => a + b)).to.equal(61229)
+      })
+    })
+  })
+})

2021/day-08/index.js

@@ -0,0 +1,3 @@
+// eslint-disable-next-line no-unused-vars
+const console = require('../helpers')
+require('./solution')

2021/day-08/solution.js

@@ -0,0 +1,52 @@
+const fs = require('fs')
+const path = require('path')
+const filePath = path.join(__dirname, 'input.txt')
+const { linesToArray } = require('../../2018/inputParser')
+const { descrambleSignal, decodeSignal, parseEntry } = require('./display')
+
+fs.readFile(filePath, { encoding: 'utf8' }, (err, initData) => {
+  if (err) throw err
+
+  initData = linesToArray(initData.trim())
+
+  const resetInput = () => {
+    // Deep copy to ensure we aren't mutating the original data
+    return JSON.parse(JSON.stringify(
+      initData.map(
+        (line) => line.split('|')
+          .map((e) => e.trim())
+      )
+    ))
+  }
+
+  const part1 = () => {
+    const data = resetInput()
+
+    return data.map((entry) => {
+      const { charCodes } = descrambleSignal(entry[0])
+      return decodeSignal(charCodes, entry[1])
+    }).reduce((total, signal) => {
+      const search = [1, 4, 7, 8]
+
+      // Find how many of our desired numbers are in the signal
+      total += signal.filter((digit) => search.includes(digit)).length
+
+      return total
+    }, 0)
+  }
+
+  const part2 = () => {
+    const data = resetInput()
+
+    return data.map(parseEntry)
+      .reduce((a, b) => a + b)
+  }
+  const answers = []
+  answers.push(part1())
+  answers.push(part2())
+
+  answers.forEach((ans, idx) => {
+    console.info(`-- Part ${idx + 1} --`)
+    console.info(`Answer: ${ans}`)
+  })
+})

README.md

@@ -9,7 +9,12 @@
 ![](https://img.shields.io/badge/stars%20⭐-14-yellow)
 ![](https://img.shields.io/badge/days%20completed-7-red)
 
-## Start a boilerplate for a new day
+## Run the currently configured default day
+`npm start`
+
+### Run in debug mode for extended logging
+`DEBUG=1 npm start`
+## Generate a boilerplate for a new day
 `npm run new`
 ### Special Instructions
 Run by modifying `index.js` to point to the puzzle you want to execute.

index.js

@@ -1 +1 @@
-require('./2021/day-07/solution')
+require('./2021/day-08/solution')

package.json

@@ -10,7 +10,8 @@
     "posttest": "nyc report --reporter=html --reporter=text-lcov > coverage.lcov",
     "lint": "standard",
     "report-coverage": "codecov",
-    "new": "npx plop --plopfile ./plop-templates/plopfile.js"
+    "new": "npx plop --plopfile ./plop-templates/plopfile.js",
+    "start": "node ./index.js"
   },
   "repository": {
     "type": "git",