leetcode[12]Integer to Roman

public class Solution {
    public String intToRoman(int num) {
        int[] values = {1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1 };  
        String[] numerals = {"M", "CM", "D", "CD", "C", "XC", "L", "XL", "X", "IX", "V", "IV", "I" };  
        StringBuilder res = new StringBuilder(); 
        for(int i=0;i<values.length;i++)
        {
            while(num>=values[i])
            {
                num-=values[i];
                res.append(numerals[i]);
            }
        }
        return res.toString();
    }
}