Day 14-2

Author: ansf

day14-2.ts

@@ -0,0 +1,102 @@
+import * as fs from "fs"
+
+const input = fs.readFileSync("input-day14.txt", "utf8")
+const lines = input.trim().split("\n")
+const recipes = lines
+    .map(line => {
+        const [i, o] = line.split("=>")
+        return [i.split(",").map(s => s.trim()).map(parse), parse(o.trim())] as const
+    })
+    .reduce((a, v) => {
+        a.set(v[1][1], v)
+        return a
+    }, new Map<Element, Recipe>())
+
+function parse(ingredient: string): Ingredient {
+    const [c, n] = ingredient.split(" ")
+    return [Number(c), n]
+}
+
+function print(recipe: Recipe) {
+    console.log(recipe[0].map(i => `${i[0]} ${i[1]}`).join(", "), " => ", recipe[1][0], recipe[1][1])
+}
+
+type Quantity = number
+type Element = string
+type Ingredient = readonly [Quantity, Element]
+type Recipe = readonly [Ingredient[], Ingredient]
+
+class Bag {
+    private readonly bag = new Map<Element, Quantity>()
+    get(e: Element) {
+        return this.bag.get(e) ?? 0
+    }
+    add(e: Element, q: Quantity) {
+        this.bag.set(e, Math.max(0, q + this.get(e)))
+    }
+    remove(e: Element, q: Quantity) {
+        this.add(e, -q)
+    }
+    delete(e: Element) {
+        this.bag.delete(e)
+    }
+    entries() {
+        return this.bag.entries()
+    }
+    get size() {
+        return this.bag.size
+    }
+}
+
+
+function oreForFuel(quantity: Quantity) {
+    const need = new Bag()
+    need.add("FUEL", quantity)
+
+    const spares = new Bag()
+
+    do {
+        const [e, q] = Array.from(need.entries()).filter(([e,]) => e !== "ORE")[0]
+        need.delete(e)
+
+        const needs = ingredients(recipes.get(e), q, spares)
+        needs.forEach(([q, e]) => {
+            need.add(e, q)
+        })
+    } while (need.size > 1)
+    return need.get("ORE")
+}
+
+function ingredients(recipe: Recipe, quantity: Quantity, spares: Bag): Ingredient[] {
+    const e = recipe[1][1]
+
+    const spare = spares.get(e)
+    quantity = Math.max(0, quantity - spare)
+    spares.remove(e, quantity)
+    if (quantity === 0) {
+        return []
+    }
+
+    const factor = Math.ceil(quantity / recipe[1][0])
+    const producing = recipe[1][0] * factor
+    spares.add(e, producing - quantity)
+    return recipe[0].map(r => ([r[0] * factor, r[1]]))
+}
+
+const maxOre = 1000000000000
+let fuelL = 1
+let fuelU = 1000000000000
+
+do {
+    let fuel = fuelL + Math.floor((fuelU - fuelL) / 2)
+    let ore = oreForFuel(fuel)
+    if (ore < maxOre && oreForFuel(fuel + 1) > maxOre) {
+        console.log(fuel)
+        break
+    }
+    if (ore > maxOre) {
+        fuelU = fuel - 1
+    } else if (ore < maxOre) {
+        fuelL = fuel + 1
+    }
+} while (true)