Create lowest-common-ancestor-of-a-binary-search-tree.py

leetCode/tree/lowest-common-ancestor-of-a-binary-search-tree.py

@@ -0,0 +1,46 @@
+# https://leetcode.com/problems/lowest-common-ancestor-of-a-binary-search-tree/
+# Definition for a binary tree node.
+# class TreeNode:
+#     def __init__(self, x):
+#         self.val = x
+#         self.left = None
+#         self.right = None
+
+class Solution:
+    def lowestCommonAncestor(self, root: 'TreeNode', p: 'TreeNode', q: 'TreeNode') -> 'TreeNode':
+        p_fathers = []
+        q_fathers = []
+        it = root
+        while it and it != p:
+            p_fathers.append(it)
+            if it.val > p.val:
+                it = it.left
+            else:
+                it = it.right
+        if it and it.val == p.val:
+            p_fathers.append(it)
+
+        it = root
+        while it and it != q:
+            q_fathers.append(it)
+            if it.val > q.val:
+                it = it.left
+            else:
+                it = it.right
+        if it and it.val == q.val:
+            q_fathers.append(it)
+
+        # print(f"p: {p}, q: {q}")
+        # print(f"p_fathers: {p_fathers}")
+        # print(f"q_fathers: {q_fathers}")
+
+        i = 0
+        len_p = len(p_fathers)
+        len_q = len(q_fathers)
+        while i < min(len_p, len_q):
+            if p_fathers[i] == q_fathers[i]:
+                i += 1
+            else:
+                break
+
+        return p_fathers[i - 1]