Search in a Binary Search Tree
<p>You are given the <code>root</code> of a binary search tree (BST) and an integer <code>val</code>.</p>

<p>Find the node in the BST that the node&#39;s value equals <code>val</code> and return the subtree rooted with that node. If such a node does not exist, return <code>null</code>.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
<img alt="" src="https://fastly.jsdelivr.net/gh/doocs/leetcode@main/solution/0700-0799/0700.Search%20in%20a%20Binary%20Search%20Tree/images/tree1.jpg" style="width: 422px; height: 302px;" />
<pre>
<strong>Input:</strong> root = [4,2,7,1,3], val = 2
<strong>Output:</strong> [2,1,3]
</pre>

<p><strong class="example">Example 2:</strong></p>
<img alt="" src="https://fastly.jsdelivr.net/gh/doocs/leetcode@main/solution/0700-0799/0700.Search%20in%20a%20Binary%20Search%20Tree/images/tree2.jpg" style="width: 422px; height: 302px;" />
<pre>
<strong>Input:</strong> root = [4,2,7,1,3], val = 5
<strong>Output:</strong> []
</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li>The number of nodes in the tree is in the range <code>[1, 5000]</code>.</li>
	<li><code>1 &lt;= Node.val &lt;= 10<sup>7</sup></code></li>
	<li><code>root</code> is a binary search tree.</li>
	<li><code>1 &lt;= val &lt;= 10<sup>7</sup></code></li>
</ul>
Tree; Binary Search Tree; Binary Tree
/**
 * Definition for a binary tree node.
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode() {}
 *     TreeNode(int val) { this.val = val; }
 *     TreeNode(int val, TreeNode left, TreeNode right) {
 *         this.val = val;
 *         this.left = left;
 *         this.right = right;
 *     }
 * }
 */
class Solution {
    public TreeNode searchBST(TreeNode root, int val) {
        if (root == null || root.val == val) {
            return root;
        }
        return root.val > val ? searchBST(root.left, val) : searchBST(root.right, val);
    }
}