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