quicksort.clj

(defn large-quicksort
  [items]
  (if (<= (count items) 1)
    items
    (let [pindex (rand-int (count items))
          p (get (vec items) pindex)
          [before after-with-p] (split-at pindex items)
          after (rest after-with-p)
          newitems (vec (concat before after))]
      #(concat
        (large-quicksort (filter (fn [i] (< i p)) newitems))
        [p]
        (large-quicksort (filter (fn [i] (>= i p)) newitems))))))


(println (trampoline (large-quicksort [3 7 8 5 2 1 9 6 4])))

user=> (trampoline (large-quicksort [3 7 8]))
(
#<RuntimeException java.lang.RuntimeException: java.lang.RuntimeException: java.lang.IllegalArgumentException: Don't know how to create ISeq from: user$large_quicksort$fn__1796>

(defn large-quicksort
  [items]
  (if (<= (count items) 1)
items
(let [pindex (rand-int (count items))
      p (get (vec items) pindex)
      [before after-with-p] (split-at pindex items)
      after (rest after-with-p)
      newitems (vec (concat before after))]
  #(concat
    (trampoline large-quicksort (filter (fn [i] (< i p)) newitems))
    [p]
    (trampoline large-quicksort (filter (fn [i] (>= i p)) newitems))))))


((large-quicksort [3 7 8 5 2 1 9 6 4]))