import java.util.*;public class BST { // instance variables private BSTNode m_root; private int m_size; // constructor public BST() { m_root = null; m_size = 0; } // This method returns the number of elements in the tree. // Do not make any changes to this method! public int size() { return m_size; } // This method clears the content of the tree. // Do not make any changes to this method! public void clear() { m_root = null; m_size = 0; } // This non-recursive method takes a string and inserts it into the binary // search tree, keeping the tree ordered. public void add(String value) { // TODO: implement this method using a non-recursive solution } // This non-recursive method returns a string that represents the in-order traversal // of the binary search tree. public String inOrder() { // TODO: implement this method using a non-recursive solution return ""; // replace this statement with your own return } // This method returns the largest element in the binary search tree. You // are not allowed to create any additional structures, including but not // limited to arrays, stacks, queues, or other trees. public String max() { // TODO: implement this method return ""; // replace this statement with your own return } // This method takes a reference to the root of the expression, evaluates // the tree, and returns the result as an int. public int evaluate(BSTNode node) { // TODO: implement this method return -1; // replace this statement with your own return }} public class BSTNode{// data membersprivate String m_value;private BSTNode m_left;private BSTNode m_right;// constuctorpublic BSTNode(String value){m_value =value;m_left = null;m_right}null;// member methodspublic String getInfo(){return m_value;}public BSTNode getLeft(){return m_left;}public BSTNode getRight(){return m_right;}public void setLeft(BSTNode left){m_left}left;%Dpublic void setRight(BSTNode right){m_right}}right; a. Completing the BST classYou are provided with the files "BSTNode.java" and "BST.java". You are required tocomplete the methods in the latter file to implement a binary search tree. This tree is designedto store only strings and it does not allow duplicate elements. You need to write the followingthree methods:add (String v) – This non-recursive method takes a String and inserts it into the binarysearch tree, keeping the tree ordered (You can use the compareTo method to makecomparisons). It does not allow inserting the same element for more than once.inOrder ()This non-recursive method builds and returns a string that represents the in-order traversal of the binary search tree.max () – This method returns the largest element in the binary search tree. You are not allowedto create any additional structures, including but not limited to arrays, stacks, queues, orother trees.evaluate () – When provided with an expression tree, this method evaluatesthe expression represented by the tree and returns the result. Forexample, it will return 108 if the root of the tree on the right is passed intothe method. This is because (15 + 21) * 3 = 108.+31521

Question

import java.util.*;public class BST {    // instance variables    private BSTNode m_root;    private int m_size;        // constructor    public BST()    {        m_root = null;        m_size = 0;    }        // This method returns the number of elements in the tree.    // Do not make any changes to this method!    public int size()    {        return m_size;    }        // This method clears the content of the tree.    // Do not make any changes to this method!    public void clear()    {        m_root = null;        m_size = 0;    }            // This non-recursive method takes a string and inserts it into the binary    // search tree, keeping the tree ordered.    public void add(String value)    {        // TODO: implement this method using a non-recursive solution    }        // This non-recursive method returns a string that represents the in-order traversal    // of the binary search tree.    public String inOrder()    {           // TODO: implement this method using a non-recursive solution                return &#34;&#34;; // replace this statement with your own return    }         // This method returns the largest element in the binary search tree. You     // are not allowed to create any additional structures, including but not     // limited to arrays, stacks, queues, or other trees.    public String max()    {        // TODO: implement this method                return &#34;&#34;; // replace this statement with your own return    }        // This method takes a reference to the root of the expression, evaluates    // the tree, and returns the result as an int.    public int evaluate(BSTNode node)    {        // TODO: implement this method                return -1; // replace this statement with your own return    }} public class BSTNode{// data membersprivate String m_value;private BSTNode m_left;private BSTNode m_right;// constuctorpublic BSTNode(String value){m_value =value;m_left = null;m_right}null;// member methodspublic String getInfo(){return m_value;}public BSTNode getLeft(){return m_left;}public BSTNode getRight(){return m_right;}public void setLeft(BSTNode left){m_left}left;%Dpublic void setRight(BSTNode right){m_right}}right; a. Completing the BST classYou are provided with the files &#34;BSTNode.java&#34; and &#34;BST.java&#34;. You are required tocomplete the methods in the latter file to implement a binary search tree. This tree is designedto store only strings and it does not allow duplicate elements. You need to write the followingthree methods:add (String v) – This non-recursive method takes a String and inserts it into the binarysearch tree, keeping the tree ordered (You can use the compareTo method to makecomparisons). It does not allow inserting the same element for more than once.inOrder ()This non-recursive method builds and returns a string that represents the in-order traversal of the binary search tree.max () – This method returns the largest element in the binary search tree. You are not allowedto create any additional structures, including but not limited to arrays, stacks, queues, orother trees.evaluate () – When provided with an expression tree, this method evaluatesthe expression represented by the tree and returns the result. Forexample, it will return 108 if the root of the tree on the right is passed intothe method. This is because (15 + 21) * 3 = 108.+31521

Accepted Answer

Answer is in given below.
Apply this common.