More clojure quicksort

quicksort2.clj

;; improved version of my first solution, cut out the let by
;; using destructuring.
(defn quicksort [[pivot & others]]
  (when pivot
    (concat
    (quicksort (filter #(>= pivot %) others))
    [pivot]
    (quicksort (filter #(< pivot %) others)))))

;; code golf style (shortest solution) - based on Tom C's solution
(defn q [[i & r]]
  (let [f (fn [s p v] (filter #(s % p) v))]
    (when i (concat (q (f <= i r)) [i] (q (f > i r))))))

;; silly multi-method (multi-dispatch) solution. Could combine 0 and 1 with a better dispatch choice
(defmulti multi-quicksort (fn [xs] (count xs)))
(defmethod multi-quicksort 0 [xs]
  xs)
(defmethod multi-quicksort 1 [xs]
  xs)
(defmethod multi-quicksort :default [[pivot & xs]]
  (concat
   (multi-quicksort (filter #(>= pivot %) xs))
   [pivot]
   (multi-quicksort (filter #(< pivot %) xs))))