A decimal number can be converted to its Hexspeak representation by first converting it to an uppercase hexadecimal string, then replacing all occurrences of the digit 0 with the letter O, and the digit 1 with the letter I. Such a representation is valid if and only if it consists only of the letters in the set {"A", "B", "C", "D", "E", "F", "I", "O"}.
Given a string num representing a decimal integer N, return the Hexspeak representation of N if it is valid, otherwise return "ERROR".
Example 1:
Input: num = "257" Output: "IOI" Explanation: 257 is 101 in hexadecimal.
Example 2:
Input: num = "3" Output: "ERROR"
Constraints:
1 <= N <= 10^12struct Solution;
#[allow(clippy::wrong_self_convention)]
impl Solution {
fn to_hexspeak(num: String) -> String {
let x: i64 = num.parse::<i64>().unwrap();
let s = format!("{:X}", x);
let mut res: Vec<char> = vec![];
for c in s.chars() {
match c {
'0' => res.push('O'),
'1' => res.push('I'),
c @ 'A'..='F' => res.push(c),
_ => return "ERROR".to_string(),
}
}
res.iter().collect()
}
}
#[test]
fn test() {
let num = "257".to_string();
let res = "IOI".to_string();
assert_eq!(Solution::to_hexspeak(num), res);
let num = "3".to_string();
let res = "ERROR".to_string();
assert_eq!(Solution::to_hexspeak(num), res);
let num = "619879596177".to_string();
let res = "ERROR".to_string();
assert_eq!(Solution::to_hexspeak(num), res);
}