RosettaCodeData/Task/Roman-numerals-Encode/Clojure/roman-numerals-encode-5.clj

21 lines
574 B
Clojure

(def roman-map
(sorted-map-by >
1 "I", 4 "IV", 5 "V", 9 "IX",
10 "X", 40 "XL", 50 "L", 90 "XC",
100 "C", 400 "CD", 500 "D", 900 "CM"
1000 "M"))
(defn a2r
([r]
(reduce str (a2r r (keys roman-map))))
([r n]
(when-not (empty? n)
(let [e (first n)
v (- r e)
roman (roman-map e)]
(cond
(< v 0) (a2r r (rest n))
(= v 0) (cons roman [])
(>= v e) (cons roman (a2r v n))
(< v e) (cons roman (a2r v (rest n))))))))