diff --git a/problems/0257.二叉树的所有路径.md b/problems/0257.二叉树的所有路径.md
index 4cafbded..195b6f94 100644
--- a/problems/0257.二叉树的所有路径.md
+++ b/problems/0257.二叉树的所有路径.md
@@ -497,7 +497,7 @@ class Solution:
 
 
 ```
-递归法+回溯（版本二）
+递归法+隐形回溯（版本一）
 ```Python
 # Definition for a binary tree node.
 # class TreeNode:
@@ -505,7 +505,6 @@ class Solution:
 #         self.val = val
 #         self.left = left
 #         self.right = right
-import copy
 from typing import List, Optional
 
 class Solution:
@@ -523,13 +522,13 @@ class Solution:
         if not node.left and not node.right:
             result.append('->'.join(map(str, path)))
         else:
-            self.generate_paths(node.left, copy.copy(path), result)
-            self.generate_paths(node.right, copy.copy(path), result)
-        path.pop()
+	     # path[:] 是隐藏回溯
+            self.generate_paths(node.left, path[:], result)
+            self.generate_paths(node.right, path[:], result)
 
 ```
 	
-递归法+隐形回溯
+递归法+隐形回溯（版本二）
 ```Python
 # Definition for a binary tree node.
 # class TreeNode: