添加0344.反转字符串Python3版本

problems/0344.反转字符串.md

@@ -157,7 +157,18 @@ class Solution {
 ```
 
 Python：
-
+```python3
+class Solution:
+    def reverseString(self, s: List[str]) -> None:
+        """
+        Do not return anything, modify s in-place instead.
+        """
+        left, right = 0, len(s) - 1
+        while(left < right):
+            s[left], s[right] = s[right], s[left]
+            left += 1
+            right -= 1
+```
 
 Go：
 ```Go