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`

Solution:

**Recursive approach**

**Iterative approach**