12.clj

(nsclojure.12
"Leetcode: 12\n
 Name: Integer to Roman\n"
 (:require [clojure.test :refer [deftest is run-tests]]))

(defonceroman-symbols
 [["M"1000] ["CM"900] ["D"500] ["CD"400] ["C"100] ["XC"90]
 ["L"50] ["XL"40] ["X"10] ["IX"9] ["V"5] ["IV"4] ["I"1]])

(defnint-to-roman
"Convert an integer to its Roman numeral representation.

 Args:
 num - An integer value to convert (1 <= num <= 3999).

 Returns:
 A string representing the Roman numeral equivalent of the integer.

 Examples:
 (int-to-roman 4) ;=> \"IV\"
 (int-to-roman 9) ;=> \"IX\"
 (int-to-roman 1994) ;=> \"MCMXCIV\""
 [num]
 {:pre [(and (integer? num) (<=1 num 3999))]}
 (loop [number num
 result ""]
 (if (zero? number)
 result
 (let [[symbol value] (first (filter #(<= (second %) number) roman-symbols))]
 (recur (- number value)
 (str result symbol))))))

(deftesttest-int-to-roman
 (is (= (int-to-roman1) "I"))
 (is (= (int-to-roman4) "IV"))
 (is (= (int-to-roman9) "IX"))
 (is (= (int-to-roman58) "LVIII"))
 (is (= (int-to-roman1994) "MCMXCIV"))
 (is (= (int-to-roman3999) "MMMCMXCIX"))
 (is (= (int-to-roman1) "I"))
 (is (= (int-to-roman3999) "MMMCMXCIX"))
 (is (thrown? AssertionError (int-to-roman0)))
 (is (thrown? AssertionError (int-to-roman4000))))

(run-tests)