0541.反转字符串II.md 增加Python版本实现3

problems/0541.反转字符串II.md

@@ -282,7 +282,7 @@ class Solution:
         return ''.join(res)
 ```
 
-### Python3 (v2):
+#### Python3 (v2):
 
 ```python
 class Solution:
@@ -297,6 +297,20 @@ class Solution:
         return s
 ```
 
+#### Python3 (v3):
+```python
+class Solution:
+    def reverseStr(self, s: str, k: int) -> str:
+        i = 0
+        chars = list(s)
+        
+        while i < len(chars):
+            chars[i:i + k] = chars[i:i + k][::-1] # 反转后，更改原值为反转后值
+            i += k * 2
+
+        return ''.join(chars)
+```
+
 ### Go：
 
 ```go