Add two methods(preOrderDisplay and postOrderDisplay) to the BST class attached below. Add calls to the main method for these two methods. (UPLOAD JAVA CODE)

BST.java

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/** * * @author Brian Hunter */ public class BST { public static BSTNode root; public BST(){ this.root = null; } public boolean find(int id){ BSTNode current = root; while(current!=null){ if(current.data==id){ return true; }else if(current.data>id){ current = current.left; }else{ current = current.right; } } return false; } public boolean delete(int id){ BSTNode parent = root; BSTNode current = root; boolean isLeftChild = false; //Case 1: The node isn't in the tree. while(current.data!=id){ parent = current; if(current.data>id){ isLeftChild = true; current = current.left; }else{ isLeftChild = false; current = current.right; } if(current ==null){ return false; } } //if i am here that means we have found the node //Case 2: if node to be deleted has no children if(current.left==null && current.right==null){ if(current==root){ root = null; } if(isLeftChild ==true){ parent.left = null; }else{ parent.right = null; } } //Case 3: if node to be deleted has only one child else if(current.right==null){ if(current==root){ root = current.left; }else if(isLeftChild){ parent.left = current.left; }else{ parent.right = current.left; } } else if(current.left==null){ if(current==root){ root = current.right; }else if(isLeftChild){ parent.left = current.right; }else{ parent.right = current.right; } } //Case 4: The node has 2 children else if(current.left!=null && current.right!=null){ //now we have found the minimum element in the right sub tree BSTNode successor = getSuccessor(current); if(current==root){ root = successor; }else if(isLeftChild){ parent.left = successor; }else{ parent.right = successor; } successor.left = current.left; } return true; } public BSTNode getSuccessor(BSTNode deleteNode){ BSTNode successsor =null; BSTNode successsorParent =null; BSTNode current = deleteNode.right; while(current!=null){ successsorParent = successsor; successsor = current; current = current.left; } //check if successor has the right child, it cannot have left child for sure // if it does have the right child, add it to the left of successorParent. //successsorParent if(successsor!=deleteNode.right){ successsorParent.left = successsor.right; successsor.right = deleteNode.right; } return successsor; } public void insert(int id){ BSTNode newBSTNode = new BSTNode(id); if(root==null){ root = newBSTNode; return; } BSTNode current = root; BSTNode parent = null; while(true){ parent = current; if(id current = current.left; if(current==null){ parent.left = newBSTNode; return; } }else{ current = current.right; if(current==null){ parent.right = newBSTNode; return; } } } } public void inOrderdisplay(BSTNode root){ if(root!=null){ inOrderdisplay(root.left); System.out.print(" " + root.data); inOrderdisplay(root.right); } } public void preOrderdisplay(BSTNode root) { if(root != null){ System.out.print(" " + root.data); preOrderdisplay(root.left); preOrderdisplay(root.right); } } public void postOrderdisplay(BSTNode root) { if(root != null) { preOrderdisplay(root.left); preOrderdisplay(root.right); System.out.print(" " + root.data); } } public static void main(String arg[]){ BST b = new BST(); b.insert(3);b.insert(8); b.insert(1);b.insert(4);b.insert(6);b.insert(2); b.insert(10);b.insert(9); b.insert(20);b.insert(25);b.insert(15);b.insert(16); System.out.println("Original Tree : "); b.inOrderdisplay(b.root); System.out.println(""); System.out.println("Check whether Node with value 4 exists : " + b.find(4)); System.out.println("Delete Node with no children (2) : " + b.delete(2)); b.inOrderdisplay(root); System.out.println(" Delete Node with one child (4) : " + b.delete(4)); b.inOrderdisplay(root); System.out.println(" Delete Node with Two children (10) : " + b.delete(10)); b.inOrderdisplay(root); } }

BSTNode.java

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/** * * @author Brian Hunter */ public class BSTNode { int data; BSTNode left; BSTNode right; public BSTNode(int d) { this.data = d; left = null; right = null; } public void setData(int d) { this.data = d; } public int getData() { return data; } }

Add two methods(preOrderDisplay and postOrderDisplay) to the BST class attached below. Add calls to the main method for these two methods. (UPLOAD JAVA CODE) BST.java /* * To change this license header, choose License Headers in Project Properties. * To change this template file, choose Tools | Templates * and open the template in the editor. */ /** * * @author Brian Hunter */ public class BST { public static BSTNode root; public BST(){ this.root = null; } public boolean find(int id){ BSTNode current = root; while(current!=null){ if(current.data==id){ return true; }else if(current.data>id){ current = current.left; }else{ current = current.right; } } return false; } public boolean delete(int id){ BSTNode parent = root; BSTNode current = root; boolean isLeftChild = false; //Case 1: The node isn't in the tree. while(current.data!=id){ parent = current; if(current.data>id){ isLeftChild = true; current = current.left; }else{ isLeftChild = false; current = current.right; } if(current ==null){ return false; } } //if i am here that means we have found the node //Case 2: if node to be deleted has no children if(current.left==null && current.right==null){ if(current==root){ root = null; } if(isLeftChild ==true){ parent.left = null; }else{ parent.right = null; } } //Case 3: if node to be deleted has only one child else if(current.right==null){ if(current==root){ root = current.left; }else if(isLeftChild){ parent.left = current.left; }else{ parent.right = current.left; } } else if(current.left==null){ if(current==root){ root = current.right; }else if(isLeftChild){ parent.left = current.right; }else{ parent.right = current.right; } } //Case 4: The node has 2 children else if(current.left!=null && current.right!=null){ //now we have found the minimum element in the right sub tree BSTNode successor = getSuccessor(current); if(current==root){ root = successor; }else if(isLeftChild){ parent.left = successor; }else{ parent.right = successor; } successor.left = current.left; } return true; } public BSTNode getSuccessor(BSTNode deleteNode){ BSTNode successsor =null; BSTNode successsorParent =null; BSTNode current = deleteNode.right; while(current!=null){ successsorParent = successsor; successsor = current; current = current.left; } //check if successor has the right child, it cannot have left child for sure // if it does have the right child, add it to the left of successorParent. //successsorParent if(successsor!=deleteNode.right){ successsorParent.left = successsor.right; successsor.right = deleteNode.right; } return successsor; } public void insert(int id){ BSTNode newBSTNode = new BSTNode(id); if(root==null){ root = newBSTNode; return; } BSTNode current = root; BSTNode parent = null; while(true){ parent = current; if(id current = current.left; if(current==null){ parent.left = newBSTNode; return; } }else{ current = current.right; if(current==null){ parent.right = newBSTNode; return; } } } } public void inOrderdisplay(BSTNode root){ if(root!=null){ inOrderdisplay(root.left); System.out.print(" " + root.data); inOrderdisplay(root.right); } } public void preOrderdisplay(BSTNode root) { if(root != null){ System.out.print(" " + root.data); preOrderdisplay(root.left); preOrderdisplay(root.right); } } public void postOrderdisplay(BSTNode root) { if(root != null) { preOrderdisplay(root.left); preOrderdisplay(root.right); System.out.print(" " + root.data); } } public static void main(String arg[]){ BST b = new BST(); b.insert(3);b.insert(8); b.insert(1);b.insert(4);b.insert(6);b.insert(2); b.insert(10);b.insert(9); b.insert(20);b.insert(25);b.insert(15);b.insert(16); System.out.println("Original Tree : "); b.inOrderdisplay(b.root); System.out.println(""); System.out.println("Check whether Node with value 4 exists : " + b.find(4)); System.out.println("Delete Node with no children (2) : " + b.delete(2)); b.inOrderdisplay(root); System.out.println(" Delete Node with one child (4) : " + b.delete(4)); b.inOrderdisplay(root); System.out.println(" Delete Node with Two children (10) : " + b.delete(10)); b.inOrderdisplay(root); } } BSTNode.java /* * To change this license header, choose License Headers in Project Properties. * To change this template file, choose Tools | Templates * and open the template in the editor. */ /** * * @author Brian Hunter */ public class BSTNode { int data; BSTNode left; BSTNode right; public BSTNode(int d) { this.data = d; left = null; right = null; } public void setData(int d) { this.data = d; } public int getData() { return data; } }