feat(2018 day-14): find the position of a specified pattern

Author: developher-net

2018/day-14/recipes.js

@@ -6,6 +6,7 @@ class Recipes {
     this.head = null
     this.tail = null
     this.length = 0
+    this.tracker = ''
     this.addFirst(recipe)
   }
 
@@ -15,6 +16,7 @@ class Recipes {
     newRecipe.prev = newRecipe
     this.head = newRecipe
     this.tail = newRecipe
+    this.tracker += recipe.toString()
     this.length++
     return this
   }
@@ -30,6 +32,7 @@ class Recipes {
     newRecipe.prev = this.head // link new recipe to old head
     this.head.next = newRecipe
     this.head = newRecipe // make new recipe the new head
+    this.tracker += recipe.toString() // Sore the sequence
     this.length++
     return this.head
   }
@@ -103,8 +106,25 @@ const calculateXAfterY = (x, y, recipes, elves) => {
   return result
 }
 
+/**
+ * Counts how many recipes are to the left of the specified pattern
+ * @param {String} pattern to search for
+ * @param {LinkedList} recipes recipe list
+ * @param {Array} elves doing the work
+ */
+const findPattern = (pattern, recipes, elves) => {
+  let position = -1
+  // Generate the sequence until the sequence exists
+  while (position < 0) {
+    loopRecipesForElves(elves, recipes, 1)
+    position = recipes.tracker.indexOf(pattern)
+  }
+  return position
+}
+
 module.exports = {
   calculateXAfterY,
+  findPattern,
   loopRecipesForElves,
   Recipes,
   totalDigitsInArray

2018/day-14/recipes.test.js

@@ -2,6 +2,7 @@
 const expect = require('chai').expect
 const {
   calculateXAfterY,
+  findPattern,
   loopRecipesForElves,
   Recipes,
   totalDigitsInArray
@@ -136,5 +137,77 @@ describe('--- Day 14: Chocolate Charts ---', () => {
         expect(actual).to.equal('5941429882')
       })
     })
+    describe('findPattern()', () => {
+      it('counts the number of recipes to the left of the specified pattern', () => {
+        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 = findPattern('51589', recipes, elves)
+        expect(actual).to.equal(9)
+      })
+    })
+    describe('findPattern()', () => {
+      it('counts the number of recipes to the left of the specified pattern', () => {
+        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 = findPattern('01245', recipes, elves)
+        expect(actual).to.equal(5)
+      })
+    })
+    describe('findPattern()', () => {
+      it('counts the number of recipes to the left of the specified pattern', () => {
+        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 = findPattern('92510', recipes, elves)
+        expect(actual).to.equal(18)
+      })
+    })
+    describe('findPattern()', () => {
+      it('counts the number of recipes to the left of the specified pattern', () => {
+        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 = findPattern('59414', recipes, elves)
+        expect(actual).to.equal(2018)
+      })
+    })
   })
 })