Good luck, Kerry!

kerry.clj

(ns kerry)

(defn make-rand-x-to-y
  "A function that uses rand-x to generate rand-y,
  where (rand-n) has the integer range [0, n)."
  [x y]
  (let [randx (fn [] (rand-int x))
        size (* x y)
        choices (into [] (take size (cycle (range y))))]
    (fn []
      (let [seed (reduce + (repeatedly size randx))]
        (choices (mod seed size))))))

(defn sample
  "Tabulate n samples of actual calls to (make-rand-x-to-y x y)
  against expected (rand-int y) results."
  [n x y]
  (let [rand-x-to-y (make-rand-x-to-y x y)
        expect (frequencies (repeatedly n (fn [] (rand-int y))))
        actual (frequencies (repeatedly n rand-x-to-y))]
    (println   (str "For " n " samples"))
    (println   (str "    expect  actual"))
    (doseq [i (range y)]
      (println (str i " : " (expect i) "  " (actual i))))))

(sample 999999 5 7)
;;
;; For 999999 samples
;;     expect  actual
;; 0 : 142779  143293
;; 1 : 142912  143126
;; 2 : 142792  143258
;; 3 : 142844  142307
;; 4 : 143530  142504
;; 5 : 142692  142854
;; 6 : 142450  142657