validate binary search tree solution

Author: PDKhan

validate-binary-search-tree/PDKhan.cpp

@@ -0,0 +1,22 @@
+class Solution {
+    public:
+        bool search(TreeNode* root, long min, long max){
+            if(root == NULL)
+                return true;
+    
+            if(root->val <= min || root->val >= max)
+                return false;
+            
+            if(search(root->left, min, root->val) == false)
+                return false;
+            
+            if(search(root->right, root->val, max) == false)
+                return false;
+            
+            return true;
+        }
+    
+        bool isValidBST(TreeNode* root) {
+            return search(root, (long)INT_MIN-1, (long)INT_MAX+1);
+        }
+    };