Quicksort in Clojure

(This was a Valentine's Day post.)

Who can understand the Order of Love? Let's find out with a Quicksort implementation in Clojure:

(defn quicksort [coll]
  (if (seq coll)
    (let [pivot   (rand-nth coll)
          pivots  (filter #(= % pivot) coll)
          less    (filter #(< % pivot) coll)
          greater (filter #(> % pivot) coll)]
      (concat (quicksort less) pivots (quicksort greater)))
    coll))

(eval)

;; Example 1

(quicksort [49 11 37 2 18])
=> (2 11 18 37 49)

(eval)

;; Example 2

(->> [4326 55357 10086 10087 56460 10084 9753 10163 63 10083 10085 9825 9829]
  (quicksort)
  (map char)
  (apply str))

(eval)

;; Result

;;; ?ღ☙♡♥❣❤❥❦❧➳💌