developher-net · developher-net · Dec 23, 2018 · Dec 22, 2018 · Dec 23, 2018 · Dec 23, 2018
diff --git a/2018/day-14/recipes.js b/2018/day-14/recipes.js
@@ -0,0 +1,111 @@
+/**
+ * Circular linked list of recipes
+ */
+class Recipes {
+  constructor (recipe) {
+    this.head = null
+    this.tail = null
+    this.length = 0
+    this.addFirst(recipe)
+  }
+
+  addFirst (recipe) {
+    const newRecipe = { value: recipe }
+    newRecipe.next = newRecipe
+    newRecipe.prev = newRecipe
+    this.head = newRecipe
+    this.tail = newRecipe
+    this.length++
+    return this
+  }
+
+  /**
+   * Adds a recipe to the linked list
+   * @param {Number} recipe value
+   */
+  addRecipe (recipe) {
+    const newRecipe = { value: recipe }
+    newRecipe.next = this.tail // link new recipe to tail
+    this.tail.prev = newRecipe
+    newRecipe.prev = this.head // link new recipe to old head
+    this.head.next = newRecipe
+    this.head = newRecipe // make new recipe the new head
+    this.length++
+    return this.head
+  }
+
+  /**
+   * Scoring the current recipes means adding new recipies base on the score value
+   * @param {Number} score of current recipe
+   */
+  scoreRecipes (score) {
+    score.toString().split('').forEach((recipe) => {
+      this.addRecipe(parseInt(recipe))
+    })
+  }
+}
+
+/**
+ * Takes an array of numbers and totals the digits
+ * @param
+ */
+const totalDigitsInArray = (arr) => {
+  return arr.reduce(
+    (acc, num) => acc + num.toString().split('')
+      .reduce((sub, digit) => sub + parseInt(digit), 0), 0)
+}
+
+/**
+ * Loops the elves through the recipes list the specified number of times
+ * @param {Array} elves list of elves
+ * @param {LinkedList} recipes list of recipes
+ * @param {Numbe} repeat count of desired iterations
+ */
+const loopRecipesForElves = (elves, recipes, repeat) => {
+  for (let x = 1; x <= repeat; x++) {
+    const score = totalDigitsInArray(elves.map((elf) => elf.value))
+    recipes.scoreRecipes(score)
+    elves.forEach((elf, idx) => {
+      const distance = elf.value + 1
+      for (let x = 0; x < distance; x++) {
+        elf = elf.next
+      }
+      elves[idx] = elf
+    })
+  }
+}
+
+/**
+ * Determines the next X recipes after the elves have generated Y recipes
+ */
+const calculateXAfterY = (x, y, recipes, elves) => {
+  let iterator = recipes.head
+  while (recipes.length <= y) {
+    loopRecipesForElves(elves, recipes, 1)
+  }
+
+  if (recipes.length === y + 1) {
+    iterator = recipes.head
+  } else {
+    // In case multidigit recipe results created more than Y
+    iterator = recipes.head.prev
+  }
+
+  while (recipes.length < x + y) {
+    loopRecipesForElves(elves, recipes, 1)
+  }
+
+  let result = ''
+  while (result.length < x) {
+    result += iterator.value.toString()
+    iterator = iterator.next
+  }
+  return result
+}
+
+module.exports = {
+  calculateXAfterY,
+  loopRecipesForElves,
+  Recipes,
+  totalDigitsInArray
+}
diff --git a/2018/day-14/recipes.test.js b/2018/day-14/recipes.test.js
@@ -0,0 +1,140 @@
+/* eslint-env mocha */
+const expect = require('chai').expect
+const {
+  calculateXAfterY,
+  loopRecipesForElves,
+  Recipes,
+  totalDigitsInArray
+} = require('./recipes')
+
+describe('--- Day 14: Chocolate Charts ---', () => {
+  describe('Part 1:', () => {
+    describe('new Recipes()', () => {
+      it('builds a linked list', () => {
+        const recipes = new Recipes(0)
+        for (let x = 1; x <= 5; x++) {
+          recipes.addRecipe(x)
+        }
+        expect(recipes.length).to.equal(6)
+        expect(recipes.head.value).to.equal(5)
+        expect(recipes.tail.value).to.equal(0)
+        expect(recipes.tail.prev).to.equal(recipes.head) // circular linked list for prev
+        expect(recipes.head.next).to.equal(recipes.tail) // circular linked list for next
+      })
+      describe('scoreRecipes()', () => {
+        it('adds new recipes based on the provided score', () => {
+          const recipes = new Recipes(0)
+          for (let x = 1; x <= 5; x++) {
+            recipes.addRecipe(x)
+          }
+          recipes.scoreRecipes(37)
+          expect(recipes.head.value).to.equal(7)
+          expect(recipes.head.prev.value).to.equal(3)
+          expect(recipes.head.prev.prev.value).to.equal(5)
+          expect(recipes.head.next).to.equal(recipes.tail)
+        })
+      })
+    })
+    describe('totalDigitsInArray()', () => {
+      it('calculates the total value of all the digits of all the numbers in the provided array', () => {
+        const expected = 34
+        const test = [1, 5, 13, 22, 3, 0, 971]
+        const actual = totalDigitsInArray(test)
+        expect(actual).to.equal(expected)
+      })
+    })
+    describe('loopRecipeForEleves()', () => {
+      it('loops through the recipe object for the specified elves the specified number of times', () => {
+        const expected = '37101012451589167792' // list of recipe values in the last iteration of the example
+        const elves = [3, 7]
+        const recipes = new Recipes(elves[0])
+        let actual = ''
+
+        elves.forEach((elf, idx) => {
+          if (idx === 0) {
+            elves[0] = recipes.head
+          } else {
+            elves[idx] = recipes.addRecipe(elf)
+          }
+        })
+
+        loopRecipesForElves(elves, recipes, 15)
+
+        let iterator = recipes.tail.next
+        actual += recipes.tail.value.toString()
+        while (iterator !== recipes.tail) {
+          actual += iterator.value.toString()
+          iterator = iterator.next
+        }
+
+        expect(expected).to.equal(actual)
+      })
+    })
+    describe('calculateXAfterY(x, y, recipe, elves)', () => {
+      it('predicts the next X results after the elves have executed Y', () => {
+        const elves = [3, 7]
+        const recipes = new Recipes(elves[0])
+        let actual = ''
+
+        elves.forEach((elf, idx) => {
+          if (idx === 0) {
+            elves[0] = recipes.head
+          } else {
+            elves[idx] = recipes.addRecipe(elf)
+          }
+        })
+
+        actual = calculateXAfterY(10, 9, recipes, elves)
+        expect(actual).to.equal('5158916779')
+      })
+      it('predicts the next X results after the elves have executed Y', () => {
+        const elves = [3, 7]
+        const recipes = new Recipes(elves[0])
+        let actual = ''
+
+        elves.forEach((elf, idx) => {
+          if (idx === 0) {
+            elves[0] = recipes.head
+          } else {
+            elves[idx] = recipes.addRecipe(elf)
+          }
+        })
+
+        actual = calculateXAfterY(10, 5, recipes, elves)
+        expect(actual).to.equal('0124515891')
+      })
+      it('predicts the next X results after the elves have executed Y', () => {
+        const elves = [3, 7]
+        const recipes = new Recipes(elves[0])
+        let actual = ''
+
+        elves.forEach((elf, idx) => {
+          if (idx === 0) {
+            elves[0] = recipes.head
+          } else {
+            elves[idx] = recipes.addRecipe(elf)
+          }
+        })
+
+        actual = calculateXAfterY(10, 18, recipes, elves)
+        expect(actual).to.equal('9251071085')
+      })
+      it('predicts the next X results after the elves have executed Y', () => {
+        const elves = [3, 7]
+        const recipes = new Recipes(elves[0])
+        let actual = ''
+
+        elves.forEach((elf, idx) => {
+          if (idx === 0) {
+            elves[0] = recipes.head
+          } else {
+            elves[idx] = recipes.addRecipe(elf)
+          }
+        })
+
+        actual = calculateXAfterY(10, 2018, recipes, elves)
+        expect(actual).to.equal('5941429882')
+      })
+    })
+  })
+})
diff --git a/2018/day-14/solution.js b/2018/day-14/solution.js
@@ -0,0 +1,25 @@
+const {
+  calculateXAfterY,
+  Recipes
+} = require('./recipes')
+
+const input = 540561
+
+const elves = [3, 7]
+const recipes = new Recipes(elves[0])
+
+elves.forEach((elf, idx) => {
+  if (idx === 0) {
+    elves[0] = recipes.head
+  } else {
+    elves[idx] = recipes.addRecipe(elf)
+  }
+})
+
+const answer = calculateXAfterY(10, input, recipes, elves)
+const answer2 = ''
+
+console.log(`-- Part 1 --`)
+console.log(`Answer: ${answer}`)
+console.log(`-- Part 2 --`)
+console.log(`Answer: ${answer2}`)
diff --git a/index.js b/index.js
@@ -0,0 +1 @@
+require('./2018/day-14/solution')