Code shared from the Rust Playground

playground.rs

//Is Unique: Implement an algorithm to determine if a string has all unique characters.
//What if you cannot use additional data structures?
use std::collections::HashMap;
fn main() {
    //println!("Hello World!");
    println!("{}", has_all_unique("asdasd"));
    println!("{}", has_all_unique_hash("asdasd"));
}

fn has_all_unique(word: &str) -> bool {
    let mut new = word.chars().collect::<Vec<char>>();
    new.sort();
    new.dedup();
    new.len() == word.len()
}

fn has_all_unique_hash(word: &str) -> bool {
    let mut hashmap = HashMap::new();
    for character in word.chars() {
        if hashmap.contains_key(&character) {
            return false;
        } else {
            hashmap.insert(character, 1);
        }
    }
    return true;
}

#[cfg(test)]
mod tests_hash {
    use super::has_all_unique_hash;
    #[test]
    fn test_asdasd() {
        assert_eq!(has_all_unique_hash("asdasd"), false);
    }
    #[test]
    fn test_hello() {
        assert_eq!(has_all_unique_hash("Hello"), false);
    }
    #[test]
    fn test_malayalam() {
        assert_eq!(has_all_unique_hash("malayalam"), false);
    }
    #[test]
    fn test_tim() {
        assert_eq!(has_all_unique_hash("tim"), true);
    }
    #[test]
    fn test_a() {
        assert_eq!(has_all_unique_hash("a"), true);
    }
    #[test]
    fn test_empty() {
        assert_eq!(has_all_unique_hash(""), true);
    }
    #[test]
    fn test_space() {
        assert_eq!(has_all_unique_hash(" "), true);
    }
    #[test]
    fn test_123() {
        assert_eq!(has_all_unique_hash("123"), true);
    }
    #[test]
    fn test_symbols_unique() {
        assert_eq!(has_all_unique_hash("!#@$%^&*("), true);
    }
    #[test]
    fn test_symbols_non_unique() {
        assert_eq!(has_all_unique_hash("!##!##!"), false);
    }
}
#[cfg(test)]
mod tests_sort {
    use super::has_all_unique;
    #[test]
    fn test_asdasd() {
        assert_eq!(has_all_unique("asdasd"), false);
    }
    #[test]
    fn test_hello() {
        assert_eq!(has_all_unique("Hello"), false);
    }
    #[test]
    fn test_malayalam() {
        assert_eq!(has_all_unique("malayalam"), false);
    }
    #[test]
    fn test_tim() {
        assert_eq!(has_all_unique("tim"), true);
    }
    #[test]
    fn test_a() {
        assert_eq!(has_all_unique("a"), true);
    }
    #[test]
    fn test_empty() {
        assert_eq!(has_all_unique(""), true);
    }
    #[test]
    fn test_space() {
        assert_eq!(has_all_unique(" "), true);
    }
    #[test]
    fn test_123() {
        assert_eq!(has_all_unique("123"), true);
    }
    #[test]
    fn test_symbols_unique() {
        assert_eq!(has_all_unique("!#@$%^&*("), true);
    }
    #[test]
    fn test_symbols_non_unique() {
        assert_eq!(has_all_unique("!##!##!"), false);
    }
}