Java Program to Perform Sorting Using B-Tree

This is a java program to implement sorting using B-Trees. Binary Search Trees are the type of B trees that self organizes. Inorder traversal of BSTs results in the sorted sequence of elements in the tree.

Here is the source code of the Java Program to Perform Sorting Using B-Tree. The Java program is successfully compiled and run on a Windows system. The program output is also shown below.

//This is a java program to perform sorting using BTree, Inorder traversal of BST results in sorting of numbers
import java.util.Random;
 
/* Class BSTNode */
class BSTNodes {
    BSTNodes left, right;
    int data;
 
    /* Constructor */
    public BSTNodes() 
    {
        left = null;
        right = null;
        data = 0;
    }
 
    /* Constructor */
    public BSTNodes(int n) 
    {
        left = null;
        right = null;
        data = n;
    }
 
    /* Function to set left node */
    public void setLeft(BSTNodes n) 
    {
        left = n;
    }
 
    /* Function to set right node */
    public void setRight(BSTNodes n) 
    {
        right = n;
    }
 
    /* Function to get left node */
    public BSTNodes getLeft() 
    {
        return left;
    }
 
    /* Function to get right node */
    public BSTNodes getRight() 
    {
        return right;
    }
 
    /* Function to set data to node */
    public void setData(int d) 
    {
        data = d;
    }
 
    /* Function to get data from node */
    public int getData() 
    {
        return data;
    }
}
 
/* Class BST */
class BT {
    private BSTNode root;
 
    /* Constructor */
    public BT() 
    {
        root = null;
    }
 
    /* Function to check if tree is empty */
    public boolean isEmpty() 
    {
        return root == null;
    }
 
    /* Functions to insert data */
    public void insert(int data) 
    {
        root = insert(root, data);
    }
 
    /* Function to insert data recursively */
    private BSTNode insert(BSTNode node, int data) 
    {
        if (node == null)
            node = new BSTNode(data);
        else 
        {
            if (data <= node.getData())
                node.left = insert(node.left, data);
            else
                node.right = insert(node.right, data);
        }
        return node;
    }
 
    /* Functions to delete data */
    public void delete(int k)
    {
        if (isEmpty())
            System.out.println("Tree Empty");
        else if (search(k) == false)
            System.out.println("Sorry " + k + " is not present");
        else 
        {
            root = delete(root, k);
            System.out.println(k + " deleted from the tree");
        }
    }
 
    private BSTNode delete(BSTNode root, int k) 
    {
        BSTNode p, p2, n;
        if (root.getData() == k) 
        {
            BSTNode lt, rt;
            lt = root.getLeft();
            rt = root.getRight();
            if (lt == null && rt == null)
                return null;
            else if (lt == null) 
            {
                p = rt;
                return p;
            }
            else if (rt == null) 
            {
                p = lt;
                return p;
            } 
            else 
            {
                p2 = rt;
                p = rt;
                while (p.getLeft() != null)
                    p = p.getLeft();
                p.setLeft(lt);
                return p2;
            }
        }
        if (k < root.getData()) 
        {
            n = delete(root.getLeft(), k);
            root.setLeft(n);
        }
        else 
        {
            n = delete(root.getRight(), k);
            root.setRight(n);
        }
        return root;
    }
 
    /* Functions to count number of nodes */
    public int countNodes() 
    {
        return countNodes(root);
    }
 
    /* Function to count number of nodes recursively */
    private int countNodes(BSTNode r) 
    {
        if (r == null)
            return 0;
        else 
        {
            int l = 1;
            l += countNodes(r.getLeft());
            l += countNodes(r.getRight());
            return l;
        }
    }
 
    /* Functions to search for an element */
    public boolean search(int val) 
    {
        return search(root, val);
    }
 
    /* Function to search for an element recursively */
    private boolean search(BSTNode r, int val) 
    {
        boolean found = false;
        while ((r != null) && !found) 
        {
            int rval = r.getData();
            if (val < rval)
                r = r.getLeft();
            else if (val > rval)
                r = r.getRight();
            else 
            {
                found = true;
                break;
            }
            found = search(r, val);
        }
        return found;
    }
 
    /* Function for inorder traversal */
    public void inorder() 
    {
        inorder(root);
    }
 
    private void inorder(BSTNode r) 
    {
        if (r != null) 
        {
            inorder(r.getLeft());
            System.out.print(r.getData() + " ");
            inorder(r.getRight());
        }
    }
 
    /* Function for preorder traversal */
    public void preorder() 
    {
        preorder(root);
    }
 
    private void preorder(BSTNode r) 
    {
        if (r != null) 
        {
            System.out.print(r.getData() + " ");
            preorder(r.getLeft());
            preorder(r.getRight());
        }
    }
 
    /* Function for postorder traversal */
    public void postorder() 
    {
        postorder(root);
    }
 
    private void postorder(BSTNode r) 
    {
        if (r != null) 
        {
            postorder(r.getLeft());
            postorder(r.getRight());
            System.out.print(r.getData() + " ");
        }
    }
}
 
public class Sort_BTree 
{
    public static int N = 20;
 
    public static void main(String args[]) 
    {
        Random random = new Random();
        BT bt = new BT();
 
        System.out
                .println("Sorting of randomly generated numbers using B TREE");
 
        for (int i = 0; i < N; i++)
            bt.insert(Math.abs(random.nextInt(100)));
 
        System.out.println("The elements of the tree: ");
        bt.preorder();
 
        System.out.println("\nThe sorted sequence is: ");
        bt.inorder();
    }
}

Output:

$ javac Sort_BTree.java
$ java Sort_BTree
 
Sorting of randomly generated numbers using B TREE
The elements of the tree: 
45 23 3 4 26 39 32 30 32 83 64 50 47 54 64 67 75 88 94 95 
The sorted sequence is: 
3 4 23 26 30 32 32 39 45 47 50 54 64 64 67 75 83 88 94 95