feature: lowest common ancestor of binary search tree revisit dfs rec…

…ursive
solairerove · Jan 12, 2024 · cb807b9 · cb807b9
1 parent 1f2d834
commit cb807b9
Showing 1 changed file with 6 additions and 5 deletions.
diff --git a/trees/LowestCommonAncestorOfABinarySearchTree.py b/trees/LowestCommonAncestorOfABinarySearchTree.py
@@ -19,15 +19,16 @@ def lowest_common_ancestor(self, root: TreeNode, p: TreeNode, q: TreeNode) -> Op
 
 # O(h) time || O(h) space
 def lowest_common_ancestor_dfs(self, root: TreeNode, p: TreeNode, q: TreeNode) -> Optional[TreeNode]:
-    mn, mx = min(p.val, q.val), max(p.val, q.val)
-
     def dfs(node):
-        if node.val > mx:
-            return dfs(node.left)
+        if not node:
+            return None
 
-        if node.val < mn:
+        if node.val < p.val and node.val < q.val:
             return dfs(node.right)
 
+        if node.val > p.val and node.val > q.val:
+            return dfs(node.left)
+
         return node
 
     return dfs(root)