playground.rs

use std::rc::{Rc, Weak};
use std::cell::RefCell;

#[derive(Debug)]
struct Node {
    me: RefCell<String>,
    children: Option<Vec<Node>>,
    parent: Option<Weak<Node>>,
}

playground.rs

use std::rc::{Rc, Weak};
use std::cell::RefCell;

#[derive(Debug)]
struct Node {
    me: RefCell<String>,
    children: Option<Vec<Node>>,
    parent: Option<Weak<Node>>,
}