AtcoderからTravelingのClojure実装

Travelingのコードがずっと時間切れで通りませんでした。

最初はpartition使って楽に書きました。

(defn abs[x]
   (if (< x 0)
        (- x)
         x))
(defn judge[[a  b c] [d e f]]
  (let [t (- d a)
        s (+ (abs (- e b)) (abs (- f c)))]
   (if (zero? (mod t s))
       true
       false)))
(def n (Integer/parseInt (read-line)))
(def t (for [i (range 0 n)] 
   (map #(Integer/parseInt %) (clojure.string/split (read-line) #"\s"))))
(def t (concat '((0 0 0)) t))
(if (some false? 
            (map #(judge
                   (first %)
                   (second %))
                   (partition 2 1 t)))
          (println "No")
          (println "Yes"))

partitionのところが遅いようなのでreduceでリストのシークを減らしました

(defn abs[x]
   (if (< x 0)
        (- x)
        x))
(def flg (atom true))
(defn judge[[a  b c] [d e f]]
  (when @flg
    (let [t (- d a)
          s (+ (abs (- e b)) (abs (- f c)))]
      (when (not (zero? (mod t s)))
        (reset! flg false))))
  [d e f])
(def n (Integer/parseInt (read-line)))
(def t (for [i (range 0 n)] 
   (map #(Integer/parseInt %) (clojure.string/split (read-line) #"\s"))))
(reduce #(judge %1 %2) '(0 0 0) t)
(if @flg
  (println "Yes")
  (println "No"))

reduceよりloop/recurが早いのでこれに変えてなんとか通りましたとさ。

(defn abs[x]
   (if (< x 0)
        (- x)
        x))
(def flg (atom true))
(defn judge[[a  b c] [d e f]]
  (when @flg
    (let [t (- d a)
          s (+ (abs (- e b)) (abs (- f c)))]
      (when (not (zero? (mod t s)))
        (reset! flg false)))))
(def n (Integer/parseInt (read-line)))
(def t (for [i (range 0 n)] 
         (map #(Integer/parseInt %) (clojure.string/split (read-line) #"\s"))))
(def t (concat '((0 0 0)) t))
(loop [t1 t]
  (when (and (next t1) @flg)
    (do
      (judge (first t1) (second t1))
      (recur (next t1)))))
(if @flg
  (println "Yes")
  (println "No"))