From f1aa928e1cc8349a26b3ceb37184a6216f272736 Mon Sep 17 00:00:00 2001
From: Asterisk <44215173+casnz1601@users.noreply.github.com>
Date: Sun, 3 Oct 2021 20:09:23 +0800
Subject: [PATCH] =?UTF-8?q?Update=200257.=E4=BA=8C=E5=8F=89=E6=A0=91?=
 =?UTF-8?q?=E7=9A=84=E6=89=80=E6=9C=89=E8=B7=AF=E5=BE=84.md?=
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修订python3语法规范lint
---
 problems/0257.二叉树的所有路径.md | 43 ++++++++++++++---------
 1 file changed, 26 insertions(+), 17 deletions(-)

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 c85186d5..f902aab2 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
@@ -404,33 +404,41 @@ class Solution {
     }
 }
 ```
-
-Python：
-```Python
+---
+Python:  
+递归法+隐形回溯
+```Python3
+# Definition for a binary tree node.
+# class TreeNode:
+#     def __init__(self, val=0, left=None, right=None):
+#         self.val = val
+#         self.left = left
+#         self.right = right
 class Solution:
-    """二叉树的所有路径 递归法"""
-
     def binaryTreePaths(self, root: TreeNode) -> List[str]:
-        path, result = '', []
+        path = ''
+        result = []
+        if not root: return result
         self.traversal(root, path, result)
         return result
     
-    def traversal(self, cur: TreeNode, path: List, result: List):
+    def traversal(self, cur: TreeNode, path: str, result: List[str]) -> None:
         path += str(cur.val)
-        # 如果当前节点为叶子节点，添加路径到结果中
-        if not (cur.left or cur.right):
+        # 若当前节点为leave，直接输出
+        if not cur.left and not cur.right:
             result.append(path)
-            return
-            
+
         if cur.left:
+            # + '->' 是隐藏回溯
             self.traversal(cur.left, path + '->', result)
-            
+        
         if cur.right:
             self.traversal(cur.right, path + '->', result)
-
 ```
-
-```python
+  
+迭代法：
+  
+```python3
 from collections import deque
 
 
@@ -457,7 +465,8 @@ class Solution:
 
         return result
 ```
-
+  
+---
 
 Go：
 ```go
@@ -482,7 +491,7 @@ func binaryTreePaths(root *TreeNode) []string {
     return res
 }
 ```
-
+---
 JavaScript:
 
 1.递归版本