Merge pull request #763 from RyouMon/master

修复 0236.二叉树的最近公共祖先.md/0235.二叉搜索树的最近公共祖先.md Python3解法

problems/0235.二叉搜索树的最近公共祖先.md

@@ -268,17 +268,30 @@ class Solution {
 递归法：
 ```python
 class Solution:
+    """二叉搜索树的最近公共祖先 递归法"""
+
     def lowestCommonAncestor(self, root: 'TreeNode', p: 'TreeNode', q: 'TreeNode') -> 'TreeNode':
-        if not root: return root  //中
-        if root.val >p.val and root.val > q.val:
-            return self.lowestCommonAncestor(root.left,p,q)  //左
-        elif root.val < p.val and root.val < q.val:
-            return self.lowestCommonAncestor(root.right,p,q)  //右
-        else: return root
+        if root.val > p.val and root.val > q.val:
+            return self.lowestCommonAncestor(root.left, p, q)
+        if root.val < p.val and root.val < q.val:
+            return self.lowestCommonAncestor(root.right, p, q)
+        return root
 ```
 
 迭代法：
+```python
+class Solution:
+    """二叉搜索树的最近公共祖先 迭代法"""
 
+    def lowestCommonAncestor(self, root: 'TreeNode', p: 'TreeNode', q: 'TreeNode') -> 'TreeNode':
+        while True:
+            if root.val > p.val and root.val > q.val:
+                root = root.left
+            elif root.val < p.val and root.val < q.val:
+                root = root.right
+            else:
+                return root
+```
 
 ## Go 
 

problems/0236.二叉树的最近公共祖先.md

@@ -264,16 +264,21 @@ class Solution {
 ## Python 
 
 ```python
-//递归
 class Solution:
+    """二叉树的最近公共祖先 递归法"""
+
     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
+        if not root or root == p or root == q:
+            return root
+        
+        left = self.lowestCommonAncestor(root.left, p, q)
+        right = self.lowestCommonAncestor(root.right, p, q)
+        
+        if left and right:
+            return root
+        if left:
+            return left
+        return right
 ```
 
 ## Go