Integer to Roman

Given an integer, convert it to a roman numeral.

Input is guaranteed to be within the range from 1 to 3999.

class Solution {

public:
    string intToRoman(int num) {
        // Note: The Solution object is instantiated only once and is reused by each test case.    
        string solution = "";
        
        string huns[] = {"", "C", "CC", "CCC", "CD", "D", "DC", "DCC", "DCCC", "CM"};
        string tens[] = {"", "X", "XX", "XXX", "XL", "L", "LX", "LXX", "LXXX", "XC"};
        string ones[] = {"", "I", "II", "III", "IV", "V", "VI", "VII", "VIII", "IX"};
        
        while (num >= 1000) {
            solution = solution + 'M';
            num -= 1000;
        }
        
        solution = solution + huns[num/100]; num %= 100;
        solution = solution + tens[num/10]; num %= 10;
        solution = solution + ones[num];
        
        return solution;
    }
};