public class BSTextends Comparablesuper T>> { // DO NOT ADD OR MODIFY INSTANCE VARIABLES.  private BSTNode root; private int size; 

 /** * Finds and retrieves the k-largest elements from the BST in sorted order,  * least to greatest.  *  * In most cases, this method will not need to traverse the entire tree to  * function properly, so you should only traverse the branches of the tree  * necessary to get the data and only do so once. Failure to do so will  * result in the efficiency penalty.  *  * EXAMPLE: Given the BST below composed of Integers:  *  * 50  * / \  * 25 75  * / \  * 12 37  * / \ \  * 10 15 40  * /  * 13  *  * kLargest(5) should return the list [25, 37, 40, 50, 75].  * kLargest(3) should return the list [40, 50, 75].  *  * Should have a running time of O(log(n) + k) for a balanced tree and a  * worst case of O(n + k).  *  * @throws java.lang.IllegalArgumentException if k > n, the number of data  * in the BST  * @param k the number of largest elements to return  * @return sorted list consisting of the k largest elements  */ public List kLargest(int k) { . . . .//code . . }

public class BSTNodeextends Comparablesuper T>> { private T data; private BSTNode left; private BSTNode right; /**  * Create a BST node with the given data.  *  * @param data the data to be stored in this node.  */  public BSTNode(T data) { this.data = data; } /**  * Get the data in this node.  *  * @return data in this node.  */  public T getData() { return data; } /**  * Set the data in this node.  *  * @param data data to be placed into the node.  */  public void setData(T data) { this.data = data; } /**  * Get the node to the left of this node.  *  * @return node to the left.  */  public BSTNode getLeft() { return left; } /**  * Set the node to the left of this node.  *  * @param left new node to the left.  */  public void setLeft(BSTNode left) { this.left = left; } /**  * Get the node to the right of this node.  *  * @return node to the right.  */  public BSTNode getRight() { return right; } /**  * Set the node to the right of this node.  *  * @param right new node to the right.  */  public void setRight(BSTNode right) { this.right = right; } }