Count the coins with clojure

count-the-coins.clj

(defn- count-change [coins offset target]
  (if (= target 0)
    1
    (loop [coins coins offset offset target target sum 0]
      (if (< offset (alength coins))
        (if (>= target (nth coins offset))
          (recur coins (inc offset) target (+ sum (count-change coins offset (- target (nth coins offset)))))
          (recur coins (inc offset) target sum))
        sum))))

test-count-the-coins.clj

(let [coins (int-array [1 5 10 25]) target 100]
  (print (count-change coins 0 target)))

reference

• https://cartesianproduct.wordpress.com/2011/03/19/the-recursive-cash-changing-algorithm/