solve : validate binary search tree

Author: SamTheKorean

validate-binary-search-tree/samthekorean.py

@@ -0,0 +1,16 @@
+# TC : O(n) where n being the number of nodes of the tree
+# SC : O(n) where n being the size of sum of every nodes
+class Solution:
+    def isValidBST(self, root: Optional[TreeNode]) -> bool:
+        def is_valid_bst(node, min_val, max_val):
+            if not node:
+                return True
+
+            if node.val <= min_val or node.val >= max_val:
+                return False
+
+            return is_valid_bst(node.left, min_val, node.val) and is_valid_bst(
+                node.right, node.val, max_val
+            )
+
+        return is_valid_bst(root, float("-inf"), float("inf"))