12. Integer to Roman

greedy

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