use std::rc::Rc;

fn main() {
    let mut li = List::new();
    li.prepend(9000);
    li.prepend(777);
    li.prepend(42);
}

struct List {
    head: Option<Rc<Node>>,
    last: Option<Rc<Node>>,
}

impl List {
    fn new() -> Self {
        Self {
            head: None,
            last: None,
        }
    }

    fn prepend(&mut self, value: i32) {
        self.head = Some(Rc::new(Node {
            value,
            next: self.head.take(),
        }));

        if self.last.is_none() {
            self.last = self.head.clone();
        }
    }
}

struct Node {
    value: i32,
    next: Option<Rc<Node>>,
}

impl Drop for Node {
    fn drop(&mut self) {
        println!("Droppe Node ({})", self.value);
    }
}