Roman Numerals Encoder.java

/*
Create a function taking a positive integer between 1 and 3999 (both included) as 
its parameter and returning a string containing the Roman Numeral representation of 
that integer.

Modern Roman numerals are written by expressing each digit separately starting with 
the left most digit and skipping any digit with a value of zero. In Roman numerals 1
990 is rendered: 1000=M, 900=CM, 90=XC; resulting in MCMXC. 2008 is written as 2000=MM, 
8=VIII; or MMVIII. 1666 uses each Roman symbol in descending order: MDCLXVI.

Example:

conversion.solution(1000); //should return "M"
Help:

Symbol    Value
I          1
V          5
X          10
L          50
C          100
D          500
M          1,000
Remember that there can't be more than 3 identical symbols in a row.

More about roman numerals - http://en.wikipedia.org/wiki/Roman_numerals
*/


public class Conversion {

    public static String solution(int n) {

            String[] oneDigit = {"", "I", "II", "III", "IV", "V", "VI", "VII", "VIII", "IX"};
            String[] twoDigits = {"", "X", "XX", "XXX", "XL", "L", "LX", "LXX", "LXXX", "XC"};
            String[] threeDigits= {"", "C", "CC", "CCC", "CD", "D", "DC", "DCC", "DCCC", "CM"};
            String[] fourDigits = {"", "M", "MM", "MMM"};

            return fourDigits[n/1000] + threeDigits[(n%1000)/100] + twoDigits[(n%100/10)] + oneDigit[n%10];
        }
}