Update 0257.二叉树的所有路径.md

problems/0257.二叉树的所有路径.md

@@ -798,8 +798,7 @@ object Solution {
 rust:
 
 ```rust
-use std::cell::RefCell;
-use std::rc::Rc;
+// 遍历
 impl Solution {
     pub fn binary_tree_paths(root: Option<Rc<RefCell<TreeNode>>>) -> Vec<String> {
         let mut res = vec![];