# LeetCode 0098 - Validate Binary Search Tree

# Validate Binary Search Tree

## Desicription

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

Assume a 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:**

1 | 2 |

Binary tree `[2,1,3]`

, return true.

**Example 2:**

1 | 1 |

Binary tree `[1,2,3]`

, return false.

## Solution

1 | /** |