链表

rust/code/link.rs

@@ -0,0 +1,56 @@
+use std::cell::RefCell;
+use std::rc::Rc;
+
+struct Link {
+    value: String,
+    next:Option<Rc<RefCell<Link>>>,
+    back:Option<Rc<RefCell<Link>>>
+}
+
+impl Link {
+    fn init(content:&str) -> Option<Rc<RefCell<Link>>> {
+        let link=Rc::new(RefCell::new(Link{value:String::from(content),next:None,back:None}));
+        link.borrow_mut().next = Some(Rc::clone(&link));
+        link.borrow_mut().back = Some(Rc::clone(&link));
+     Some(link)
+    }
+    fn add(old_link:Option<Rc<RefCell<Link>>>,content:&str) -> Option<Rc<RefCell<Link>>> {
+        let old_link_ref=old_link.as_ref();
+        let new_link=Rc::new(RefCell::new(Link{
+            value:String::from(content),
+            next:Some(Rc::clone(old_link_ref?.borrow().next.as_ref()?)),
+            back:Some(Rc::clone(old_link_ref?))
+        }));
+
+        let back_link=old_link_ref?.borrow().back.clone()?;
+        if Rc::ptr_eq(old_link_ref?, old_link_ref?.borrow().back.as_ref()?) {
+            back_link.borrow_mut().back = Some(Rc::clone(&new_link));
+        }
+        back_link.borrow_mut().next = Some(Rc::clone(&new_link));
+        Some(new_link)
+    }
+    fn del(link:Option<Rc<RefCell<Link>>>) -> Option<Rc<RefCell<Link>>> {
+        let link_ref=link.clone()?;
+        let back_link=link_ref.borrow().back.clone()?;
+        let next_link=link_ref.borrow().next.clone()?;
+        if Rc::ptr_eq(&link_ref, &next_link) {
+            drop(link);
+            None
+        }else {
+            back_link.borrow_mut().next=Some(Rc::clone(&next_link));
+            next_link.borrow_mut().back=Some(Rc::clone(&back_link));
+            Some(next_link)
+        }
+    }
+
+}
+
+fn main() {
+    let link=Link::init("lsy");
+    let new_link=Link::add(link,"input");
+    let n_n_link=Link::del(new_link);
+    let n_n_nlink=Link::del(n_n_link);
+    if let None=n_n_nlink {
+        println!("删除成功")
+    }
+}