feat(2013 day-14): solution to part 1, calculate X recipes after Y recipes

Author: developher-net

2018/day-14/recipes.js

@@ -72,12 +72,39 @@ const loopRecipesForElves = (elves, recipes, repeat) => {
       }
       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)
+  }
 
-    console.log(recipes.head.value)
+  let result = ''
+  while (result.length < x) {
+    result += iterator.value.toString()
+    iterator = iterator.next
   }
+  return result
 }
 
 module.exports = {
+  calculateXAfterY,
   loopRecipesForElves,
   Recipes,
   totalDigitsInArray

2018/day-14/recipes.test.js

@@ -1,6 +1,7 @@
 /* eslint-env mocha */
 const expect = require('chai').expect
 const {
+  calculateXAfterY,
   loopRecipesForElves,
   Recipes,
   totalDigitsInArray
@@ -69,5 +70,71 @@ describe('--- Day 14: Chocolate Charts ---', () => {
         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')
+      })
+    })
   })
 })

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}`)