advent-6-fast.clj

(set! *warn-on-reflection* true)
(set! *unchecked-math* :warn-on-boxed)

(defn parse-int [s]
  (Integer/parseInt s))

(defn get-coords [^long n [^long sx ^long sy] [^long ex ^long ey]]
  (for [x (range sx (inc ex))
        y (range sy (inc ey))]
    (+ (long x) (* (long n) (long y)))))

(defn parse [inst]
  (let [[_ cmd sx sy ex ey] (re-find #"(turn on|turn off|toggle) (\d+),(\d+) through (\d+),(\d+)" inst)
        sx (parse-int sx)
        sy (parse-int sy)
        ex (parse-int ex)
        ey (parse-int ey)]
    [cmd [sx sy] [ex ey]]))


(defn update-board! [board command coords]
  (condp = command
    "turn on" (doseq [i coords] (aset ^booleans board i true))
    "turn off" (doseq [i coords] (aset ^booleans board i false))
    "toggle" (doseq [i coords] (aset ^booleans board i ^boolean (not (aget ^booleans board i))))))


(->>
 (let [n 1000
       board (make-array Boolean/TYPE (* n n))]
   (doseq [line (str/split-lines (slurp "a6.txt"))]
     (let [[cmd s e] (parse line)]
       (update-board! board cmd (get-coords n s e))))
   board)
 (filter identity)
 count)