idomatic rust (#1652)

* idomatic rust

* Update linkedlist queue/deque

Author: rongyi

codes/rust/chapter_array_and_linkedlist/my_list.rs

@@ -19,8 +19,7 @@ struct MyList {
 impl MyList {
     /* 构造方法 */
     pub fn new(capacity: usize) -> Self {
-        let mut vec = Vec::new();
-        vec.resize(capacity, 0);
+        let mut vec = vec![0; capacity];
         Self {
             arr: vec,
             capacity,
@@ -92,7 +91,7 @@ impl MyList {
         };
         let num = self.arr[index];
         // 将将索引 index 之后的元素都向前移动一位
-        for j in (index..self.size - 1) {
+        for j in index..self.size - 1 {
             self.arr[j] = self.arr[j + 1];
         }
         // 更新元素数量
@@ -111,7 +110,7 @@ impl MyList {
     }
 
     /* 将列表转换为数组 */
-    pub fn to_array(&mut self) -> Vec<i32> {
+    pub fn to_array(&self) -> Vec<i32> {
         // 仅转换有效长度范围内的列表元素
         let mut arr = Vec::new();
         for i in 0..self.size {

codes/rust/chapter_stack_and_queue/linkedlist_deque.rs

@@ -120,7 +120,7 @@ impl<T: Copy> LinkedListDeque<T> {
                     }
                 }
                 self.que_size -= 1; // 更新队列长度
-                Rc::try_unwrap(old_front).ok().unwrap().into_inner().val
+                old_front.borrow().val
             })
         }
         // 队尾出队操作
@@ -136,7 +136,7 @@ impl<T: Copy> LinkedListDeque<T> {
                     }
                 }
                 self.que_size -= 1; // 更新队列长度
-                Rc::try_unwrap(old_rear).ok().unwrap().into_inner().val
+                old_rear.borrow().val
             })
         }
     }
@@ -163,12 +163,16 @@ impl<T: Copy> LinkedListDeque<T> {
 
     /* 返回数组用于打印 */
     pub fn to_array(&self, head: Option<&Rc<RefCell<ListNode<T>>>>) -> Vec<T> {
-        if let Some(node) = head {
-            let mut nums = self.to_array(node.borrow().next.as_ref());
-            nums.insert(0, node.borrow().val);
-            return nums;
+        let mut res: Vec<T> = Vec::new();
+        fn recur<T: Copy>(cur: Option<&Rc<RefCell<ListNode<T>>>>, res: &mut Vec<T>) {
+            if let Some(cur) = cur {
+                res.push(cur.borrow().val);
+                recur(cur.borrow().next.as_ref(), res);
+            }
         }
-        return Vec::new();
+
+        recur(head, &mut res);
+        res
     }
 }
 

codes/rust/chapter_stack_and_queue/linkedlist_queue.rs

@@ -67,7 +67,7 @@ impl<T: Copy> LinkedListQueue<T> {
                 }
             }
             self.que_size -= 1;
-            Rc::try_unwrap(old_front).ok().unwrap().into_inner().val
+            old_front.borrow().val
         })
     }
 
@@ -78,12 +78,18 @@ impl<T: Copy> LinkedListQueue<T> {
 
     /* 将链表转化为 Array 并返回 */
     pub fn to_array(&self, head: Option<&Rc<RefCell<ListNode<T>>>>) -> Vec<T> {
-        if let Some(node) = head {
-            let mut nums = self.to_array(node.borrow().next.as_ref());
-            nums.insert(0, node.borrow().val);
-            return nums;
+        let mut res: Vec<T> = Vec::new();
+
+        fn recur<T: Copy>(cur: Option<&Rc<RefCell<ListNode<T>>>>, res: &mut Vec<T>) {
+            if let Some(cur) = cur {
+                res.push(cur.borrow().val);
+                recur(cur.borrow().next.as_ref(), res);
+            }
         }
-        return Vec::new();
+
+        recur(head, &mut res);
+
+        res
     }
 }
 

codes/rust/chapter_stack_and_queue/linkedlist_stack.rs

@@ -45,16 +45,10 @@ impl<T: Copy> LinkedListStack<T> {
     /* 出栈 */
     pub fn pop(&mut self) -> Option<T> {
         self.stack_peek.take().map(|old_head| {
-            match old_head.borrow_mut().next.take() {
-                Some(new_head) => {
-                    self.stack_peek = Some(new_head);
-                }
-                None => {
-                    self.stack_peek = None;
-                }
-            }
+            self.stack_peek = old_head.borrow_mut().next.take();
             self.stk_size -= 1;
-            Rc::try_unwrap(old_head).ok().unwrap().into_inner().val
+
+            old_head.borrow().val
         })
     }