0700. Search in a Binary Search Tree

https://leetcode.com/problems/search-in-a-binary-search-tree

Description

You are given the root of a binary search tree (BST) and an integer val.

Find the node in the BST that the node's value equals val and return the subtree rooted with that node. If such a node does not exist, return null.

Example 1:

**Input:** root = [4,2,7,1,3], val = 2
**Output:** [2,1,3]

Example 2:

**Input:** root = [4,2,7,1,3], val = 5
**Output:** []

Constraints:

• The number of nodes in the tree is in the range [1, 5000].

• 1 <= Node.val <= 107

• root is a binary search tree.

• 1 <= val <= 107

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