Solution (leetcode-in-java 1.20 API)

java.lang.Object
- g0001_0100.s0098_validate_binary_search_tree.Solution

```
public class Solution
extends Object
```
98 - Validate Binary Search Tree.
Medium

Given the root of a binary tree, determine if it is a valid binary search tree (BST).

A valid BST is defined as follows:
- The left subtree of a node contains only nodes with keys less than the node’s key.
- The right subtree of a node contains only nodes with keys greater than the node’s key.
- Both the left and right subtrees must also be binary search trees.
Example 1:

Input: root = [2,1,3]

Output: true

Example 2:

Input: root = [5,1,4,null,null,3,6]

Output: false

Explanation: The root node’s value is 5 but its right child’s value is 4.

Constraints:
- The number of nodes in the tree is in the range [1, 10⁴].
- -2³¹ <= Node.val <= 2³¹ - 1

- Constructor Summary
  
  Constructors
  Constructor Description
  
  Solution()
- Method Summary
  
  All Methods Instance Methods Concrete Methods
  Modifier and Type Method Description
  
  boolean isValidBST(TreeNode root)
  - Methods inherited from class java.lang.Object
    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail
- Solution
```
public Solution()
```

Method Detail

isValidBST

public boolean isValidBST(TreeNode root)