searchBST.swift

class Solution {
    func searchBST(_ root: TreeNode?, _ val: Int) -> TreeNode? {
        
        guard let node = root else { return nil }
        
        if node.val == val { return root }
        if node.val > val  { return searchBST(node.left, val) }
        if node.val < val  { return searchBST(node.right, val) }
        
        return nil
    }
}