Integer to Roman

Given an integer, convert it to a roman numeral.

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

Solution: 

I = 1;
V = 5;
X = 10;
L = 50;
C = 100;
D = 500;
M = 1000;

其中每两个阶段的之间有一个减法的表示，比如900=CM， C写在M前面表示M-C。

所以有：I = 1; IV = 4; V = 5; IX = 9; X = 10; XL = 40; L = 50; XC = 90; C = 100; CD = 400; D = 500; CM = 900; M = 1000;

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