struct Solution;
impl Solution {
fn int_to_roman(mut num: i32) -> String {
let mapping: Vec<(i32, &str)> = vec![
(1, "I"),
(2, "II"),
(3, "III"),
(4, "IV"),
(5, "V"),
(6, "VI"),
(7, "VII"),
(8, "VIII"),
(9, "IX"),
(10, "X"),
(20, "XX"),
(30, "XXX"),
(40, "XL"),
(50, "L"),
(60, "LX"),
(70, "LXX"),
(80, "LXXX"),
(90, "XC"),
(100, "C"),
(200, "CC"),
(300, "CCC"),
(400, "CD"),
(500, "D"),
(600, "DC"),
(700, "DCC"),
(800, "DCCC"),
(900, "CM"),
(1000, "M"),
(2000, "MM"),
(3000, "MMM"),
];
let mut res: String = "".to_string();
for (x, s) in mapping.iter().rev() {
if num >= *x {
res += s;
num -= x;
} else {
continue;
}
if num == 0 {
break;
}
}
res
}
}
#[test]
fn test() {
let num = 3;
let res = "III".to_string();
assert_eq!(Solution::int_to_roman(num), res);
let num = 1994;
let res = "MCMXCIV".to_string();
assert_eq!(Solution::int_to_roman(num), res);
}