public class Node { int key; Node left, right, parent; public Node () {} public Node (int num) { key = num; left = null; right = null; parent = null; } The most important thing is that a node as an object has four attributes: key, left, right, parent. Key holds the value of the node. Left and right refer to the left and right children nodes. Parent refers to the parent node. To finish the design of your BST class, you will be working on the following attributes/methods: • Insert: This method accepts one parameter, the target value (an integer), and will add a new node with that value into the Binary Search Tree. This method returns the root of the updated Binary Search Tree. public Node insert(int target) Search: This method accepts one parameter, the target value, and returns a boolean. If the target value is found, this method returns true, otherwise false. public boolean search(int target) • Delete: This method accepts one parameter, the target value, and will delete the node with the target value if such a node exists. This method returns the root of the updated Binary Search Tree. You might need to create a set of other supporting methods for the delete method. public Node delete(int target) The above methods should NOT be declared as static, and you are required to use the given Node class.

Please create a class named BST based on the information in the second screenshot. You don't have to modify the class Node. After that, please use the BST class and Node class to create a class BSTApp. Please make sure to use the same class name so that I don't get confused. Also, please make sure to use the following code as a starting point. 

import java.util.*;

public class BSTTest{
public static void main(String[] args) {
// perform at least one test on each operation of your BST

}

private int[] randomArray(int size) {
// remove the two lines
int[] arr = new int[1];
return arr;
}

// the parameters and return are up to you to define; this method needs to be uncommented
// private test() {
//
// }
}

Base of class Node

public class Node {
int key;
Node left, right, parent;

public Node() {}

public Node(int num) {
key = num;
left = null;
right = null;
parent = null;
}
}

Base of class BST

import java.util.*;

class BST {
// do not change this
private Node root;
private ArrayList<Integer> data;

// DO NOT MODIFY THIS METHOD
public BST() {
root = null;
data = new ArrayList<Integer>(0);
}

// DO NOT MODIFY THIS METHOD
public ArrayList<Integer> getData() {
return data;
}

// DO NOT MODIFY THIS METHOD
public void inOrderTraversal() {
inOrderTraversal(root);
}

// DO NOT MODIFY THIS METHOD
private void inOrderTraversal(Node node) {
if (node != null) {
inOrderTraversal(node.left);
data.add(node.key);
inOrderTraversal(node.right);
}
}

// search
public boolean search(int target) {
// remove this line
return false;
}

// insert
public Node insert(int target) {
// remove this line
return root;
}

// note: you may need to implement several supporting methods for delete
public Node delete(int target) {
// remove this line
return root;
}

// you are welcome to add any supporting methods
}