Rust Set

set.rs

use std::{collections::HashMap, hash::Hash};

#[derive(Debug)]
struct Set<T> {
    m: HashMap<T, ()>,
}

impl<T> Set<T>
where
    T: Eq + Hash + Copy,
{
    fn new() -> Self {
        Set { m: HashMap::new() }
    }

    fn push(&mut self, item: &T) {
        self.m.insert(*item, ());
    }

    fn contains(&self, item: &T) -> bool {
        self.m.contains_key(item)
    }

    fn remove(&mut self, item: &T) -> Option<T> {
        match self.m.remove(item) {
            Some(_v) => Some(*item),
            None => None,
        }
    }
}

fn main() {
    let mut s = Set::new();
    
    for i in 0..10 {
        s.push(&i);
    }

    let item = 5;
    println!("{} in set: {}", item, s.contains(&item));

    s.remove(&item);
}