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.
 * type TreeNode struct {
 *     Val int
 *     Left *TreeNode
 *     Right *TreeNode
 * }
 */
 func searchBST(root *TreeNode, val int) *TreeNode {
    if root == nil || root.Val == val {
        return root
    }
    if root.Val > val {
        return searchBST(root.Left, val)
    }
    return searchBST(root.Right, val)
}