gistfile1.rs

fn encode_username(username: &str) -> u64 {
    let mut encoded = 0;

    for character in username.chars() {
        let rune = character.to_lowercase() as u64;

        encoded *= 37;

        encoded += rune - match rune {
            97..122 => 96,
            48..57 => 21,
            _ => 0
        };
    }

    encoded
}

fn encode_username(username: &str) -> u64 {
    username.chars().fold(0, |encoded, character| {
        let rune = character.to_lowercase() as u64;

        (encoded * 37) + rune - match rune {
            97..122 => 96,
            48..57 => 21,
            _ => 0
        }
    })
}

fn encode_username(username: &str) -> u64 {
    username.chars().map(|c| c.to_lowercase() as u64).fold(0, |enc, c| {
        (enc * 37) + c - match c {
            97..122 => 96,
            48..57 => 21,
            _ => 0
        }
    })
}