Validate BST

leetcode/ValidateBST.cpp

@@ -0,0 +1,30 @@
+#include<bits/stdc++.h>
+using namespace std;
+/**
+ * Definition for a binary tree node.
+ * struct TreeNode {
+ *     int val;
+ *     TreeNode *left;
+ *     TreeNode *right;
+ *     TreeNode() : val(0), left(nullptr), right(nullptr) {}
+ *     TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
+ *     TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
+ * };
+ */
+class Solution {
+public:
+
+   bool isValid(TreeNode* root, long min, long max){
+        if(!root){
+            return true;
+        }
+       if(root->val>min && root->val<max){
+          return isValid(root->left, min, root->val) && isValid(root->right, root->val, max);
+       }
+       return false;
+
+    }
+    bool isValidBST(TreeNode* root) {
+       return isValid(root, LONG_MIN, LONG_MAX);
+    }
+};