main.clj

(ns intrv)

;; max
(apply max '(1 2 3 4 5 5 4 3 2 1 5))

;; min
(apply min '(1 2 3 4 5 5 4 3 2 1 5))

;; mean
(let [arr '(1 2 3 4 5 5 4 3 2 1 5)]
  (/ (reduce + arr) (double (count arr))))

;; median
(let [arr '(1 2 3 4 5 5 4 3 2 1 5)
      size   (count arr)
      sorted (sort arr)
      a (nth sorted (/ (- size 1) 2))
      b (nth sorted (/ size 2))
      r (double (/ (+ a b) 2))] r)

;; mode
;; The frequencies function returns a map of values -> frequencies
;; One can treat a map as a sequence of key-value pairs
;; If one sorts the sequence by value - second item in each pair -
;; the last item in the sequence will represent the mode
(first (last (sort-by second (frequencies arr)))))

;; reverse
(reverse '(1 2 3 4 5 5 4 3 2 1 5))