Integer to Roman

Given an integer, convert it to a roman numeral.

The number is guaranteed to be within the range from 1 to 3999.

Example

4 -> IV

12 -> XII

21 -> XXI

99 -> XCIX

Think

• Store special integer value and its corresponding roman value;
• Get a loop to minus the integer value from large to small (if n greater than that integer value), then get index and the corresponding roman value;

Solution:

public class Solution {
    /**
     * @param n The integer
     * @return Roman representation
     */
    public String intToRoman(int n) {
        // 
        int[] numTab = {1,4,5,9,10,40,50,90,100,400,500,900,1000};
        String[] romanTab = {"I", "IV", "V", "IX", "X", "XL", "L", "LC", "C", "CD", "D", "DM","M"};

        StringBuilder sb = new StringBuilder();
        for(int i = numTab.length - 1; i >= 0; i--) {
            while(n >= numTab[i]) {
                sb.append(romanTab[i]);
                n -= numTab[i];
            }
        }
        return sb.toString();
    }
}