Complete the implementation of the findNode method below.
Purpose: Search the given subtree, rooted at parameter subRoot, for a node containing the element e.
Return: If e is found, return reference to the TreeNode object containing e. If e is not found, return null.
Note: You may use recursion or iteration as per your preference. You may assume that e is not null.
private TreeNode findNode(E e, TreeNode subRoot) {
// your code goes here
}