valid bst

Author: E-1on

validate-binary-search-tree/Sung-Heon.py

@@ -0,0 +1,12 @@
+class Solution:
+    def isValidBST(self, root):
+        def validate(node, min_val, max_val):
+            if not node:
+                return True
+
+            if node.val <= min_val or node.val >= max_val:
+                return False
+
+            return validate(node.left, min_val, node.val) and validate(node.right, node.val, max_val)
+
+        return validate(root, float('-inf'), float('inf'))