Karate Chop Kata in Clojure

chop.clj

(ns chop (:use clojure.test))

(defn chop [n nums]
  (loop [nums nums offset 0]
    (if (empty? nums)
      -1
      (let [i (int (/ (count nums) 2)) x (nth nums i)]
        (cond
          (= x n) (+ offset i)
          (> x n) (recur (take i nums) offset)
          (< x n) (recur (take-last (- (count nums) (inc i)) nums) (inc i)))))))

(deftest chop-test
  (is (= -1 (chop 3 [])))
  (is (= -1 (chop 3 [1])))
  (is (=  0 (chop 1 [1])))

  (is (=  0 (chop 1 [1 3 5])))
  (is (=  1 (chop 3 [1 3 5])))
  (is (=  2 (chop 5 [1 3 5])))
  (is (= -1 (chop 0 [1 3 5])))
  (is (= -1 (chop 2 [1 3 5])))
  (is (= -1 (chop 4 [1 3 5])))
  (is (= -1 (chop 6 [1 3 5])))

  (is (=  0 (chop 1 [1 3 5 7])))
  (is (=  1 (chop 3 [1 3 5 7])))
  (is (=  2 (chop 5 [1 3 5 7])))
  (is (=  3 (chop 7 [1 3 5 7])))
  (is (= -1 (chop 0 [1 3 5 7])))
  (is (= -1 (chop 2 [1 3 5 7])))
  (is (= -1 (chop 4 [1 3 5 7])))
  (is (= -1 (chop 6 [1 3 5 7])))
  (is (= -1 (chop 8 [1 3 5 7])))
  )

(run-tests)

Nice :)