Just another update

Task/Roman-numerals-Encode/Clojure/roman-numerals-encode-2.clj

@@ -1,31 +1,17 @@
-(def arabic-roman-map
-     {1 "I", 5 "V",
-      10 "X", 50 "L",
-      100 "C", 500 "D",
-      1000 "M",
-      4 "IV", 9 "IX",
-      40 "XL", 90 "XC",
-      400 "CD", 900 "CM" })
+(def roman-map
+  (sorted-map
+    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"))
 
-(def arabic-roman-map-sorted-keys
-     (sort (keys arabic-roman-map)))
+(defn int->roman [n]
+  {:pre (integer? n)}
+  (loop [res (StringBuilder.), n n]
+    (if-let [v (roman-map n)]
+      (str (.append res v))
+      (let [[k v] (->> roman-map keys (filter #(> n %)) last (find roman-map))]
+        (recur (.append res v) (- n k))))))
 
-(defn find-value-in-coll
-  [coll k]
-  (let [aval (find coll k)]
-  (if (nil? aval) "" (val aval))))
-
-(defn to-roman
-  [result n]
-  (let
-      [closest-key-for-n (last (filter #(> n %) arabic-roman-map-sorted-keys))
-       roman-value-for-n (find-value-in-coll arabic-roman-map n)
-       roman-value-for-closet-to-n (find-value-in-coll arabic-roman-map
-						      closest-key-for-n)]
-       (if (or (<= n 0)(contains? arabic-roman-map n))
-	 (conj result roman-value-for-n)
-	 (recur (conj result roman-value-for-closet-to-n)
-		(- n closest-key-for-n)))))
-
-Usage: >(to-roman [] 1999)
-result: ["M" "CM" "XC" "IX"]
+(int->roman 1999)
+; "MCMXCIX"

Task/Roman-numerals-Encode/Clojure/roman-numerals-encode-3.clj

@@ -1,8 +1,7 @@
-(defn a2r
-  [a]
-  (let [rv [1000 500 100 50 10 5 1]
+(defn a2r [a]
+  (let [rv '(1000 500 100 50 10 5 1)
         rm (zipmap rv "MDCLXVI")
-        dv (->> rv (take-nth 2) next (#(interleave % %)))]
+        dv (->> rv (take-nth 2) next #(interleave % %))]
     (loop [a a rv rv dv dv r nil]
       (if (<= a 0)
         r