Find the longest palindrome in a string. #Rust #Polindrome

palindrome.rs

use std::collections::HashMap;

pub fn longest_palindrome(s: String) -> String {
    let mut poly: HashMap<&str, usize> = Default::default();
    for substr in s.split(" ") {
        let len = substr.len();
        let mid = (len / 2) as usize;
        if substr[0..mid] == substr[mid..len].chars().rev().collect::<String>() {
            poly.insert(substr, len);
        }
    }
    
    let mut max = ("", 0);
    'sort: for (k, v) in poly {
        if max.1 < v {
            max = (k, v);
            continue 'sort;
        }
    }

    max.0.to_string()
}

fn main() {
    assert_eq!(
        longest_palindrome("abba sad asd fasdf sadf adddda sfsd".to_string()),
        "adddda".to_string()
    );
}