Решение на упр.08 задача 1 от Константин Илиев
Към профила на Константин Илиев
Код
use std::rc::Rc;
struct List<T> {
head: Link<T>,
}
type Link<T> = Option<Rc<Node<T>>>;
struct Node<T> {
elem: T,
next: Link<T>,
}
impl<T> List<T> {
pub fn new() -> Self {
List { head: None }
}
pub fn head(&self) -> Option<&T> {
self.head.as_ref().map(|node| &node.elem)
}
pub fn tail(&self) -> List<T> {
List{
head: self.head.as_ref().and_then(|node| {
node.next.clone()
}),
}
}
pub fn prepend(&self, value: T) -> List<T> {
let new_node = Node {
elem: value,
next: self.head.clone(),
};
List { head: Some(Rc::new(new_node)),}
}
pub fn iter(&self) -> Iter<'_, T> {
Iter{
next: self.head.as_ref().map(|node| &**node),
}
}
}
struct Iter<'a, T> {
next: Option<&'a Node<T>>,
}
impl<'a, T> Iterator for Iter<'a, T> {
type Item = &'a T;
fn next(&mut self) -> Option<Self::Item> {
self.next.map(|node| {
self.next = node.next.as_ref().map(|next_node| &**next_node);
&node.elem
})
}
}
// за да предотварим stack overflow ще имплементираме // ръчно trait Drop
impl<T> Drop for List<T> {
fn drop(&mut self){
let mut cur_link = self.head.take();
while let Some(rc_node) = cur_link {
if let Ok(mut node) = Rc::try_unwrap(rc_node) {
cur_link = node.next.take();
}else {
break;
}
}
}
}
fn main() {
let mut list = List::new();
for i in 0..1_000_000 {
list = list.prepend(i);
}
std::mem::drop(list);
}