236. Lowest Common Ancestor of a Binary Tree

Author: Partho Biswas

README.md

@@ -349,6 +349,7 @@ Check this [golden](https://tinyurl.com/ujopecz) post.
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 |29| **[528. Random Pick with Weight](https://tinyurl.com/vf8bruk)**| [Python](https://tinyurl.com/wu6rdaw/528_Random_Pick_with_Weight.py)| **[Vid 1](https://tinyurl.com/usd5r25)**, **[Art 1](https://tinyurl.com/rgwt57q)** | Medium | Very tricky |
+|30| **[236. Lowest Common Ancestor of a Binary Tree](https://tinyurl.com/y54e6gco)**| [Python](https://tinyurl.com/wu6rdaw/236_Lowest_Common_Ancestor_of_a_Binary_Tree.py)| **[Vid 1](https://tinyurl.com/udf9oa9)**, **[Vid 2](https://tinyurl.com/stknbyu)**, **[Algoexpert.io](https://tinyurl.com/wwz4m5t)**, **[Official](https://tinyurl.com/yx28t8ff)**, **[Art 1](https://tinyurl.com/v86wcky)**, **[Art 2](https://tinyurl.com/tu7jdzq)**, **[Art 3](https://tinyurl.com/tgvyy7p)** | Medium | TODO: Check Again. Very Important |
 
 </p>
 </details>

leetcode.com/python/236_Lowest_Common_Ancestor_of_a_Binary_Tree.py

@@ -0,0 +1,30 @@
+# Definition for a binary tree node.
+# class TreeNode(object):
+#     def __init__(self, x):
+#         self.val = x
+#         self.left = None
+#         self.right = None
+
+# https://tinyurl.com/tu7jdzq
+class Solution(object):
+    def lowestCommonAncestor(self, root, p, q):
+        """
+        :type root: TreeNode
+        :type p: TreeNode
+        :type q: TreeNode
+        :rtype: TreeNode
+        """
+        if not root:
+            return None
+        if p == root or q == root:
+            return root
+        left = self.lowestCommonAncestor(root.left, p, q)
+        right = self.lowestCommonAncestor(root.right, p, q)
+        if left and right:
+            return root
+        if not left:
+            return right
+        if not right:
+            return left
+
+