src/adventofcode2019/day02.clj

   1 (ns adventofcode2019.day02
   2     [:require [adventofcode2019.lib :refer :all]
   3               [clojure.string :as str]
   4               [clojure.math.combinatorics :as combo]])
   5
   6 (def opcodes {1 +, 2 *})
   7 (defn perform-operation [[opcode fst snd thd] program]
   8   (let [opcode-fn (opcodes opcode)
   9         fst-val (program fst)
  10         snd-val (program snd)]
  11     (assoc program thd (opcode-fn fst-val snd-val))))
  12
  13 (defn intcode [program]
  14   (loop [program program
  15          counter 0]
  16     (let [opcode (program counter)]
  17       (if (= opcode 99)
  18         program
  19         (recur (perform-operation (map program (take 4 (iterate inc counter)))
  20                                   program)
  21                (+ counter 4))))))
  22
  23 (defn check-inputs [input noun verb]
  24   (let [fixed-input (assoc input 1 noun 2 verb)]
  25     (first (intcode fixed-input))))
  26
  27 (defn day02 []
  28   (let [input (mapv parse-int (get-list-from-file (input-file) #","))
  29         [noun verb] (first (filter (fn [[noun verb]] (= (check-inputs input noun verb) 19690720))
  30                                    (combo/cartesian-product (range 100) (range 100))))]
  31     (println (check-inputs input 12 2)) ;; part 1
  32     (println (+ (* 100 noun) verb)))) ;; part 2