src/adventofcode2019/day05.clj

   1 (ns adventofcode2019.day02
   2     [:require [adventofcode2019.lib :refer :all]
   3               [clojure.string :as str]])
   4
   5 (def operations {1 [#(assoc %4 %3 (+ %1 %2)) 3]
   6                  2 [#(assoc %4 %3 (* %1 %2)) 3]
   7                  3 [#(do (println (%2 %1)) %2) 1]
   8                  4 [#(assoc %2 %1 (parse-int (read-line))) 1]})
   9 (def decode-op (memoize (fn [opcode]
  10   (let [str-code (format "%05d" opcode)
  11         [f3 f2 f1] (map #(= \1 %) (take 3 str-code))
  12         op (parse-int (str/join (drop 3 str-code)))
  13         [operation arg-ct] (operations op)]
  14     [(case arg-ct
  15        1 #(operation ((if f1 identity %1) %2) %1)
  16        3 #(operation ((if f1 identity %1) %2)
  17                      ((if f2 identity %1) %3)
  18                      ((if f3 identity %1) %4) %1)
  19        nil) arg-ct]))))
  20
  21 (defn perform-operation [program counter]
  22    (let [opcode (program counter)
  23          [operation arg-ct] (decode-op opcode)
  24          args (->> (iterate inc counter)
  25                    (rest)
  26                    (take arg-ct)
  27                    (map program))]
  28      [(apply operation program args)
  29       (+ counter arg-ct 1)]))
  30
  31 (defn intcode [program]
  32   (loop [[program counter] [program 0]]
  33     (let [opcode (program counter)]
  34       (if (= opcode 99)
  35         program
  36         (recur (perform-operation program counter))))))
  37
  38 (defn day02 []
  39   (let [input (mapv parse-int (get-list-from-file (input-file) #","))]
  40     (part1 "see below")
  41     (intcode input)
  42     #_(part2)))