Hello World

Other "Hello World" solutions.

// The &'static here means the return type has a static lifetime.
// This is a Rust feature that you don't need to worry about now.
pub fn hello() -> &'static str {
    "Hello, World!"
}

Leap

Other "Leap" solutions.

pub fn is_leap_year(year: u64) -> bool {
    return year % 400 == 0 || (year % 4 == 0 && year % 100 != 0);
}

Nth Prime

Other "Nth Prime" solutions.

pub fn nth(n: u32) -> u32 {
    unimplemented!("What is the 0-indexed {}th prime number?", n)
}

Raindrops

Other "Raindrops" solutions.

pub fn raindrops(n: u32) -> String {
    let rain = [(3, "Pling"), (5, "Plang"), (7, "Plong")]
        .into_iter()
        .filter(|&(number, _)| n % number == 0)
        .map(|&(_, sound)| sound)
        .collect::<Vec<&str>>()
        .join("");
    return if rain.is_empty() { n.to_string() } else { rain };
}

Reverse String

Other "Reverse String" solutions.

pub fn reverse(input: &str) -> String {
    input.chars().rev().collect::<String>()
}