linked-list.rs

use std::cell::RefCell;
use std::rc::Rc;

pub struct SimpleLinkedList<T> {
    head: Option<Rc<RefCell<Element<T>>>>,
}

pub struct Element<T> {
    data: T,
    next: Option<Rc<RefCell<Element<T>>>>,
}

impl<T> SimpleLinkedList<T> {
    pub fn new() -> Self {
        SimpleLinkedList { head: None }
    }

    pub fn len(&self) -> usize {
        let mut ln = 0;
        let mut cur_option = self.head.as_ref().map(|x| x.clone());
        while let Some(cur) = cur_option {
            ln += 1;
            cur_option = cur.borrow().next.as_ref().map(|x| x.clone());
        }
        return ln;
    }

    pub fn push(&mut self, element: T) {
        let mut tail: Option<Rc<RefCell<Element<T>>>> = None;
        let mut cur_option = self.head.as_ref().map(|x| x.clone());
        while let Some(cur) = cur_option {
            cur_option = cur.borrow().next.as_ref().map(|x| x.clone());
            tail = Some(cur);
        }

        match tail.as_ref() {
            Some(e) => {
                e.borrow_mut().next = Some(Rc::new(RefCell::new(Element {
                    data: element,
                    next: None,
                })));
            }
            None => {
                self.head = Some(Rc::new(RefCell::new(Element {
                    data: element,
                    next: None,
                })));
            }
        }
    }
}