Add RomanNumeralUtil (TheAlgorithms#2434)

sokratis12GR · web-flow · commit 599278b9b1c6 · 2021-10-09T11:45:43.000+03:00
diff --git a/Maths/RomanNumeralUtil.java b/Maths/RomanNumeralUtil.java
@@ -0,0 +1,37 @@
+/**
+ * Translates numbers into the Roman Numeral System.
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/Roman_numerals">Roman numerals</a>
+ * @author Sokratis Fotkatzikis
+ * @version 1.0
+ */
+public class RomanNumeralUtil {
+
+    private static final int MIN_VALUE = 1;
+    private static final int MAX_VALUE = 5999;
+    //1000-5999
+    private static final String[] RN_M = {"", "M", "MM", "MMM", "MMMM", "MMMMM"};
+    //100-900
+    private static final String[] RN_C = {"", "C", "CC", "CCC", "CD", "D", "DC", "DCC", "DCCC", "CM"};
+    //10-90
+    private static final String[] RN_X = {"", "X", "XX", "XXX", "XL", "L", "LX", "LXX", "LXXX", "XC"};
+    //1-9
+    private static final String[] RN_I = {"", "I", "II", "III", "IV", "V", "VI", "VII", "VIII", "IX"};
+
+    public static String generate(int number) {
+        if (number < MIN_VALUE || number > MAX_VALUE) {
+            throw new IllegalArgumentException(
+                    String.format(
+                            "The number must be in the range [%d, %d]",
+                            MIN_VALUE,
+                            MAX_VALUE
+                    )
+            );
+        }
+
+        return RN_M[number / 1000] +
+                RN_C[number % 1000 / 100] +
+                RN_X[number % 100 / 10] +
+                RN_I[number % 10];
+    }
+}
