添加 0236. 二叉树的最近公共祖先 python版本

added python version of code

Author: jojoo15

problems/0236.二叉树的最近公共祖先.md

@@ -263,8 +263,24 @@ class Solution {
 ```
 
 Python：
-
-
+```python
+# Definition for a binary tree node.
+# class TreeNode:
+#     def __init__(self, x):
+#         self.val = x
+#         self.left = None
+#         self.right = None
+//递归
+class Solution:
+    def lowestCommonAncestor(self, root: 'TreeNode', p: 'TreeNode', q: 'TreeNode') -> 'TreeNode':
+        if not root or root == p or root == q: return root  //找到了节点p或者q，或者遇到空节点
+        left = self.lowestCommonAncestor(root.left,p,q)  //左
+        right = self.lowestCommonAncestor(root.right,p,q)  //右
+        if left and right: return root  //中: left和right不为空，root就是最近公共节点
+        elif left and not right: return left  //目标节点是通过left返回的
+        elif not left and right: return right  //目标节点是通过right返回的
+        else: return None  //没找到
+```
 Go：
 ```Go
 func lowestCommonAncestor(root, p, q *TreeNode) *TreeNode {