From 282d882d531480c83920cfeddaf88cbd5fe6065c Mon Sep 17 00:00:00 2001
From: rongyi <sqrongyi@163.com>
Date: Mon, 20 May 2024 15:26:21 +0800
Subject: [PATCH] Idiomatic rust

---
 .../preorder_traversal_i_compact.rs                    |  8 ++++----
 .../preorder_traversal_ii_compact.rs                   | 10 +++++-----
 .../preorder_traversal_iii_compact.rs                  | 10 +++++-----
 3 files changed, 14 insertions(+), 14 deletions(-)

diff --git a/codes/rust/chapter_backtracking/preorder_traversal_i_compact.rs b/codes/rust/chapter_backtracking/preorder_traversal_i_compact.rs
index 462197c7f..489668760 100644
--- a/codes/rust/chapter_backtracking/preorder_traversal_i_compact.rs
+++ b/codes/rust/chapter_backtracking/preorder_traversal_i_compact.rs
@@ -10,7 +10,7 @@ use std::{cell::RefCell, rc::Rc};
 use tree_node::{vec_to_tree, TreeNode};
 
 /* 前序遍历：例题一 */
-fn pre_order(res: &mut Vec<Rc<RefCell<TreeNode>>>, root: Option<Rc<RefCell<TreeNode>>>) {
+fn pre_order(res: &mut Vec<Rc<RefCell<TreeNode>>>, root: Option<&Rc<RefCell<TreeNode>>>) {
     if root.is_none() {
         return;
     }
@@ -19,8 +19,8 @@ fn pre_order(res: &mut Vec<Rc<RefCell<TreeNode>>>, root: Option<Rc<RefCell<TreeN
             // 记录解
             res.push(node.clone());
         }
-        pre_order(res, node.borrow().left.clone());
-        pre_order(res, node.borrow().right.clone());
+        pre_order(res, node.borrow().left.as_ref());
+        pre_order(res, node.borrow().right.as_ref());
     }
 }
 
@@ -32,7 +32,7 @@ pub fn main() {
 
     // 前序遍历
     let mut res = Vec::new();
-    pre_order(&mut res, root);
+    pre_order(&mut res, root.as_ref());
 
     println!("\n输出所有值为 7 的节点");
     let mut vals = Vec::new();
diff --git a/codes/rust/chapter_backtracking/preorder_traversal_ii_compact.rs b/codes/rust/chapter_backtracking/preorder_traversal_ii_compact.rs
index fa0672bd2..3fcda5c11 100644
--- a/codes/rust/chapter_backtracking/preorder_traversal_ii_compact.rs
+++ b/codes/rust/chapter_backtracking/preorder_traversal_ii_compact.rs
@@ -13,7 +13,7 @@ use tree_node::{vec_to_tree, TreeNode};
 fn pre_order(
     res: &mut Vec<Vec<Rc<RefCell<TreeNode>>>>,
     path: &mut Vec<Rc<RefCell<TreeNode>>>,
-    root: Option<Rc<RefCell<TreeNode>>>,
+    root: Option<&Rc<RefCell<TreeNode>>>,
 ) {
     if root.is_none() {
         return;
@@ -25,10 +25,10 @@ fn pre_order(
             // 记录解
             res.push(path.clone());
         }
-        pre_order(res, path, node.borrow().left.clone());
-        pre_order(res, path, node.borrow().right.clone());
+        pre_order(res, path, node.borrow().left.as_ref());
+        pre_order(res, path, node.borrow().right.as_ref());
         // 回退
-        path.remove(path.len() - 1);
+        path.pop();
     }
 }
 
@@ -41,7 +41,7 @@ pub fn main() {
     // 前序遍历
     let mut path = Vec::new();
     let mut res = Vec::new();
-    pre_order(&mut res, &mut path, root);
+    pre_order(&mut res, &mut path, root.as_ref());
 
     println!("\n输出所有根节点到节点 7 的路径");
     for path in res {
diff --git a/codes/rust/chapter_backtracking/preorder_traversal_iii_compact.rs b/codes/rust/chapter_backtracking/preorder_traversal_iii_compact.rs
index 1c834fe64..db5a27e3b 100644
--- a/codes/rust/chapter_backtracking/preorder_traversal_iii_compact.rs
+++ b/codes/rust/chapter_backtracking/preorder_traversal_iii_compact.rs
@@ -13,7 +13,7 @@ use tree_node::{vec_to_tree, TreeNode};
 fn pre_order(
     res: &mut Vec<Vec<Rc<RefCell<TreeNode>>>>,
     path: &mut Vec<Rc<RefCell<TreeNode>>>,
-    root: Option<Rc<RefCell<TreeNode>>>,
+    root: Option<&Rc<RefCell<TreeNode>>>,
 ) {
     // 剪枝
     if root.is_none() || root.as_ref().unwrap().borrow().val == 3 {
@@ -26,10 +26,10 @@ fn pre_order(
             // 记录解
             res.push(path.clone());
         }
-        pre_order(res, path, node.borrow().left.clone());
-        pre_order(res, path, node.borrow().right.clone());
+        pre_order(res, path, node.borrow().left.as_ref());
+        pre_order(res, path, node.borrow().right.as_ref());
         // 回退
-        path.remove(path.len() - 1);
+        path.pop();
     }
 }
 
@@ -42,7 +42,7 @@ pub fn main() {
     // 前序遍历
     let mut path = Vec::new();
     let mut res = Vec::new();
-    pre_order(&mut res, &mut path, root);
+    pre_order(&mut res, &mut path, root.as_ref());
 
     println!("\n输出所有根节点到节点 7 的路径，路径中不包含值为 3 的节点");
     for path in res {