I'm trying to implement a generic binary search tree. I'm inserting 7 integers and want them to return with inOrder traversal however it's only returning 4 values out of order. Then I check if the tree contains a specific value but it always returns null and i'm unsure why. I'll post the code below, any idea's on why my output is what it is? I know my issues are probably within my insert and find methods, but unsure why, some clarification would be nice. Appreciate any advice, thanks!
Output when inserting integers 15, 10, 20, 5, 13, 11, 19:
run:
InOrder:
Inorder traversal: 10 15 11 19
Is 11 in the tree? null
BUILD SUCCESSFUL (total time: 0 seconds)
Node.class:
class Node<E> {
protected E element;
protected Node<E> left;
protected Node<E> right;
public Node(E e) {
element = e;
}
}
BinarySearchTree.class:
class BinarySearchTree<E extends Comparable<E>> {
private Node<E> root;
public BinarySearchTree() {
root = null;
}
public Node find(E e) {
Node<E> current = root;
while (e.compareTo(current.element) != 0) {
if (e.compareTo(current.element) < 0) {
current = current.left;
}
else {
current = current.right;
}
if (current == null) {
return null;
}
}
return current;
}
public void insert(E e) {
Node<E> newNode = new Node<>(e);
if (root == null) {
root = newNode;
} else {
Node<E> current = root;
Node<E> parent = null;
while (true) {
parent = current;
if (e.compareTo(current.element) < 0) {
current = current.left;
}
if (current == null) {
parent.left = newNode;
return;
} else {
current = current.right;
if (current == null) {
parent.right = newNode;
return;
}
}
}
}
}
public void traverse(int traverseType) {
switch(traverseType) {
case 1: System.out.print("\nPreorder traversal: ");
preOrder(root);
break;
case 2: System.out.print("\nInorder traversal: ");
inOrder(root);
break;
case 3: System.out.print("\nPostorder traversal: ");
postOrder(root);
break;
}
System.out.println();
}
private void inOrder(Node<E> localRoot) {
if (localRoot != null) {
inOrder(localRoot.left);
System.out.print(localRoot.element + " ");
inOrder(localRoot.right);
}
}
private void preOrder(Node<E> localRoot) {
if (localRoot != null) {
System.out.print(localRoot.element + " ");
preOrder(localRoot.left);
preOrder(localRoot.right);
}
}
private void postOrder(Node<E> localRoot) {
if (localRoot != null) {
postOrder(localRoot.left);
postOrder(localRoot.right);
System.out.print(localRoot.element + " ");
}
}
}
Main class:
public class BST_Test{
public static void main(String[] args) {
testInteger();
}
static void testInteger() {
BinarySearchTree<Integer> itree = new BinarySearchTree<>();
itree.insert(15);
itree.insert(10);
itree.insert(20);
itree.insert(5);
itree.insert(13);
itree.insert(11);
itree.insert(19);
// Traverse tree
System.out.print("InOrder: ");
itree.traverse(2);
// Search for an element
System.out.println("Is 11 in the tree? " + itree.find(11));
}
}
The cause is your poorly formatted code is hiding the fact your insert method is incorrect.
This if statement does not have an opening curly brace { (and subsequently the closing curly brace } since it compiles), so as a result only the subsequent statement is included in this if block:
if (e.compareTo(current.element) < 0)
current = current.left
This means the following is executed regardless of whether the condition above is true...
if (current == null) {
parent.left = newNode;
return;
} ...
... and as a result if current != null, your insertion will then proceed to the right:
... else {
current = current.right;
if (current == null) {
parent.right = newNode;
return;
}
}
In full your current erroneous code, when formatted/indented appropriately is:
public void insert(E e) {
Node<E> newNode = new Node<>(e);
if (root == null) {
root = newNode;
} else {
Node<E> current = root;
Node<E> parent = null;
while (true) {
parent = current;
if (e.compareTo(current.element) < 0) // missing { ...
current = current.left; // ... so only this is in the if block
if (current == null) {
parent.left = newNode;
return;
} else { // oops, this should be else to the e.compareTo(current.element) < 0 condition
current = current.right;
if (current == null) {
parent.right = newNode;
return;
}
}
}
}
}
Fixed code (assuming duplicates are allowed):
public void insert(E e) {
Node<E> newNode = new Node<>(e);
if (root == null) {
root = newNode;
} else {
Node<E> current = root;
Node<E> parent = null;
while (true) {
parent = current;
if (e.compareTo(current.element) < 0) {
current = current.left;
if (current == null) {
parent.left = newNode;
return;
}
} else {
current = current.right;
if (current == null) {
parent.right = newNode;
return;
}
}
}
}
}
Moral of the story: Keeping your code well-formatted and using curly braces for blocks will save you headaches.
So I have a binary tree with data and I have currently written a remove method for the binary tree that should remove a node while still maintaining the binary tree as a balanced tree.
Currently I am doing the remove like this:
public Node remove(K key) {
return removeHelper(key, root, null);
}
public Node removeHelper(K key, Node targetNode, Node parent) {
if (targetNode == null) {
return targetNode;
} else {
if (key.compareTo(targetNode.key) == 0) {
// we have found the item we are looking for!
// CASE #1 - The target node does not have any children
if (targetNode.left == null && targetNode.right == null) {
if (parent != null) {
if (parent.left.equals(targetNode)) {
parent.left = null;
} else if (parent.right.equals(targetNode)) {
parent.right = null;
}
}
// CASE #2. target node only has a one child, right or left.
} else if (targetNode.left == null) {
targetNode = targetNode.right;
} else if (targetNode.right == null) {
targetNode = targetNode.left;
// CASE #3 - It has 2 children.
} else {
Node temp = targetNode;
Node rightMin = FindMin(temp.right);
targetNode.key = rightMin.key;
targetNode.value = rightMin.value;
}
} else if (key.compareTo(targetNode.key) < 0) {
return removeHelper(key, targetNode.left, targetNode);
} else if (key.compareTo(targetNode.key) > 0) {
return removeHelper(key, targetNode.right, targetNode);
} else {
return targetNode;
}
}
return targetNode;
}
and here is the FindMin method:
//Finding the minimum node in this subtree passed in
private Node FindMin(Node rootNode) {
if (rootNode.left == null) {
return rootNode;
} else {
return FindMin(rootNode.left);
}
}
And then I am trying to test the removal of nodes like such:
BinarySearchTree<Integer, String> tree = new BinarySearchTree<Integer, String>();
tree.put(40, "Forty");
tree.put(20, "Twenty");
tree.put(60, "Sixty");
tree.put(10, "Ten");
tree.put(30, "Thirty");
tree.put(50, "Fifty");
tree.put(70, "Seventy");
tree.put(4, "four");
tree.remove(70);
tree.remove(60);
System.out.println(tree);
And the output from this is:
(4:four)(10:Ten)(20:Twenty)(30:Thirty)(40:Forty)(50:Fifty)(60:Sixty)
As you can see, the 70 is being remove successfully but the 60 is not being removed for some reason. I tried changing around my code a bit but I usually run into a stackoverflow error when doing so.
Anyone see an issue or case I am missing here?
So i have 3 methods 1 that adds a node to the binary tree using the traverseAdd method, and another method which finds the location of where a value would be placed within the tree based on its parent node. I would like to eliminate the traverseAdd method and use the findLocation method within the add method to add the new value to the BST.
public void add(int val) {
/*Adds a new node to the binary tree after traversing the tree and figuring out where it belongs*/
Node nodeObjToAdd = new Node(val);
if(root == null){
//if node root is not null root = new node value
root = nodeObjToAdd;
}
Node nodeTraversed = root;
traverseAdd(nodeTraversed, nodeObjToAdd);
}
private void traverseAdd(Node node, Node nodeObjToAdd){
/*Traverses tree and finds a place to add the node to be added by comparing values of the left child and right child of the
* focus node*/
if(nodeObjToAdd.value < node.value){
if(node.leftChild == null){
node.leftChild = nodeObjToAdd;
}
else {
//if the val < the root.value set int he constructor
traverseAdd(node.leftChild, nodeObjToAdd);
}
}
else if(nodeObjToAdd.value > node.value) {
if (node.rightChild == null) {
node.rightChild = nodeObjToAdd;
} else {
traverseAdd(node.rightChild, nodeObjToAdd);
}
}
}
public Node findNodeLocation(Node rootNode, int val) {
/*returns where a the Node after which the value would be added.*/
if(val < rootNode.value && rootNode.leftChild != null){
return rootNode.leftChild;
}
if(val >= rootNode.value && rootNode.rightChild != null){
return rootNode.rightChild;
}
else
return this.root;
}
public void add(int val) {
if (root == null) {
root = new Node(val);
}
Node cur = root;
Node next = null;
while (true) {
next = findNodeLocation(cur, val);
if (next != cur) {
cur = next;
} else {
break;
}
}
if (val < cur.value) {
cur.leftChild = new Node(val);
} else {
cur.rightChild = new Node(val);
}
}
I think this should work
Iterator words = treeSearch.getItems().iterator();
int addCount = 0;
while (words.hasNext())
{
numWords++;
rootNode = add(objectToReference, addCount++, (ITreeSearch) words.next(), 0, rootNode);
}
//Add to the Tree
private TernaryTreeNode add(Object storedObject, int wordNum, ITreeSearch treeSearch, int pos, TernaryTreeNode parentNode) throws NoSearchValueSetException
{
if (parentNode == null)
{
parentNode = new TernaryTreeNode(treeSearch.getNodeValue(pos));
}
if (parentNode.lessThan(treeSearch, pos))
{
parentNode.left = add(storedObject, wordNum, treeSearch, pos, parentNode.left);
}
else if (parentNode.greaterThan(treeSearch, pos))
{
parentNode.right = add(storedObject, wordNum, treeSearch, pos, parentNode.right);
}
else
{
if (pos < treeSearch.getNumberNodeValues())
{
parentNode.mid = add(storedObject, wordNum, treeSearch, pos + 1, parentNode.mid);
}
else
{
numberOfObjectsStored++;
parentNode.addStoredData(storedObject);
}
}
return parentNode;
}
This a snippet of my code in my Ternary Tree which I use for inserting a Name of a person(can hav multiple words in a name, like Michele Adams, Tina Joseph George, etc). I want to convert the above recursion to a for loop / while iterator.
Please guide me on this.
General idea in replacing recursion with iteration is to create a state variable, and update it in the loop by following the same rules that you follow in your recursive program. This means that when you pick a left subtree in the recursive program, you update the state to reference the left subtree; when you go to the right subtree, the state changes to reference the right subtree, and so on.
Here is an example of how to rewrite the classic insertion into binary tree without recursion:
public TreeNode add(TreeNode node, int value) {
// Prepare the node that we will eventually insert
TreeNode insert = new TreeNode();
insert.data = value;
// If the parent is null, insert becomes the new parent
if (node == null) {
return insert;
}
// Use current to traverse the tree to the point of insertion
TreeNode current = node;
// Here, current represents the state
while (true) {
// The conditional below will move the state to the left node
// or to the right node, depending on the current state
if (value < current.data) {
if (current.left == null) {
current.left = insert;
break;
} else {
current = current.left;
}
} else {
if (current.right == null) {
current.right = insert;
break;
} else {
current = current.right;
}
}
}
// This is the original node, not the current state
return node;
}
Demo.
Thanks dasblinkenlight..
This is my logic for replacing the above recursive function for a ternary tree.
Iterator words = treeSearch.getItems().iterator();
while (words.hasNext())
{
for (int i = 0; i < word.getNumberNodeValues(); i++)
{
add_Non_Recursive(objectToReference, word, i);
}
}
//Add to Tree
private void add_Non_Recursive(Object storedObject, ITreeSearch treeSearch, int pos) throws NoSearchValueSetException
{
TernaryTreeNode currentNode = rootNode;
// Start from a node(parentNode). If there is no node, then we create a new node to insert into the tree.
// This could even be the root node.
if (rootNode == null)
{
rootNode = new TernaryTreeNode(treeSearch.getNodeValue(pos));
}
else
{
while (currentNode != null)
{
if (currentNode.lessThan(treeSearch, pos))
{
if (currentNode.left == null)
{
currentNode.left = new TernaryTreeNode(treeSearch.getNodeValue(pos));
currentNode = null;
}
else
{
currentNode = currentNode.left;
}
}
else if (currentNode.greaterThan(treeSearch, pos))
{
if (currentNode.right == null)
{
currentNode.right = new TernaryTreeNode(treeSearch.getNodeValue(pos));
currentNode = null;
}
else
{
currentNode = currentNode.right;
}
}
else
{
if (currentNode.mid == null)
{
currentNode.mid = new TernaryTreeNode(treeSearch.getNodeValue(pos));
currentNode = null;
}
else
{
currentNode = currentNode.mid;
}
}
}
}
}
But I dropped this logic as it wasnt great in performing, it took more time than the recursive counterpart.
I am trying to implement BST algorithm using Cormen's pseudo code yet having issue.
Here is my Code for Node:
public class Node {
Node left;
Node right;
int value;
Node(int value){
this.value = value;
this.left = null;
this.right = null;
}
}
and for the Bstree:
public class Btree {
Node root;
Btree(){
this.root = null;
}
public static void inorderWalk(Node n){
if(n != null){
inorderWalk(n.left);
System.out.print(n.value + " ");
inorderWalk(n.right);
}
}
public static Node getParent(Btree t, Node n){
Node current = t.root;
Node parent = null;
while(true){
if (current == null)
return null;
if( current.value == n.value ){
break;
}
if (current.value > n.value){
parent = current;
current = current.left;
}
else{ //(current.value < n.value)
parent = current;
current = current.right;
}
}
return parent;
}
public static Node search(Node n,int key){
if(n == null || key == n.value ){
return n;
}
if(key < n.value){
return search(n.left,key);
}
else{
return search(n.right,key);
}
}
public static Node treeMinimum(Node x){
if(x == null){
return null;
}
while(x.left != null){
x = x.left;
}
return x;
}
public static Node treeMaximum(Node x){
if(x == null){
return null;
}
while(x.right != null){
x = x.right;
}
return x;
}
public static Node treeSuccessor(Btree t,Node x){
if (x.right == null){
return treeMinimum(x.right);
}
Node y = getParent(t,x);
while(y != null && x == y.right){
x = y;
y = getParent(t,y);
}
return y;
}
public static Btree insert(Btree t,Node z){
Node y = null;
Node x = t.root;
while(x != null){
y = x;
if(z.value < x.value)
x = x.left;
else
x = x.right;
}
Node tmp = getParent(t,z);
tmp = y;
if(y == null){
t.root = z;
}
else if(z.value < y.value)
y.left = z;
else
y.right = z;
return t;
}
public static Btree delete(Btree t,Node z){
Node y,x;
if (z.left == null || z.right == null)
y = z;
else
y = treeSuccessor(t,z);
if (y.left != null)
x = y.left;
else
x = y.right;
if (x != null){
Node tmp = getParent(t,x);
tmp = getParent(t,y);
}
if (getParent(t,y) == null ){
t.root = x;
}
else{
if( y == getParent(t,y).left ){
getParent(t,y).left = x;
}
else{
getParent(t,y).right = x;
}
}
if(y != z){
z.value = y.value;
}
return t;
}
public static void main(String[] args){
Btree test = new Btree();
Node n1 = new Node(6);
Node n2 = new Node(3);
Node n3 = new Node(9);
Node n4 = new Node(1);
Node n5 = new Node(16);
Node n6 = new Node(4);
Node n7 = new Node(2);
Node n8 = new Node(11);
Node n9 = new Node(13);
test = insert(test,n1);
test = insert(test,n2);
test = insert(test,n3);
test = insert(test,n4);
test = insert(test,n5);
test = insert(test,n6);
test = insert(test,n7);
test = insert(test,n8);
test = insert(test,n9);
inorderWalk(test.root);
System.out.println();
test = delete(test,n8);
inorderWalk(test.root);
System.out.println();
test = delete(test,n5);
inorderWalk(test.root);
System.out.println();
test = delete(test,n2);
inorderWalk(test.root);
System.out.println();
test = delete(test,n1);
inorderWalk(test.root);
}
}
The main problem is with the remove part, sometimes it is working as intended, sometimes removing wrongly and sometimes null pointer exception. What can be the issue ?
Ps: this is NOT a homework
Some immediate problems with your code: your treeSuccessor starts with
if (x.right == null){
return treeMinimum(x.right);
}
which should be if (x.right != null), of course.
Your insert code has the lines
Node tmp = getParent(t,z);
tmp = y;
where you assign to tmp and immediately assign to it again. It doesn't seem to me that you need these lines at all, since you don't use tmp further on. At this moment, you have y being the node to whose child z gets inserted, so just delete these lines.
Again, in delete, you have the lines
if (x != null){
Node tmp = getParent(t,x);
tmp = getParent(t,y);
}
where you don't actually do anything, since tmp is not visible outside this snippet. And further on, in delete, you repeat the expression getParent(t,y), which can be an expensive operation, so you should compute it only once and assign it to some variable.
But in general, your code, though it seems correct (probably apart from delete, which I did not understand completely but which looks suspicious), does not much resemble typical binary tree code. You don't really need the getParent and treeSuccessor methods to implement search, insert, and delete. The basic structure that you have for search works for the others too, with the following modifications:
with insert, when you get to a null link, instead of returning null, insert the element to that point
with delete, when you find the element, if it has only one (or no) child, replace it with that child, and if it has two children, replace it with either the maximum of the left child tree or the minimum of the right child tree
Both of these require in addition that you keep track of the parent node while descending into the tree, but that's the only modification you need to make to search. In particular, there is never any need to go upwards in the tree (which treeSuccessor will do).
First of all, your implementation got nothing to do with object orientation (except using objects). The insert and delete operations for example should operate ON the Tree.
Besides, I would recommend to implement the Node class as a static member of the Tree class.
public class Tree {
private Node root = null;
// remainder omitted
public boolean insert(int element) {
if (isEmpty()) {
root = new Node(element);
return true; // empty tree, Node could be inserted, return true
}
Node current = root; // start at root
Node parent; // the current Node's parent
do {
parent = current;
if (element < current.element) {
current = current.left; // go to left
} else if (element > current.element) {
current = current.right; // go to right
} else {
return false; // duplicates are NOT allowed, element could not be inserted -> return false
} while (current != null);
Node node = new Node(element);
if (element < current.element) {
parent.left = node;
} else {
parent.right = node;
}
return true; // node successfully inserted
}
public boolean isEmpty() {
return root == null;
}
private static class Node { // static member class
Node left = null;
Node right = null;
final int element;
Node(int element) {
this.element = element;
}
}
}
...what is up with your delete code? It doesn't make a lot of sense. I would consider rewriting it in a more logical way. Without the meaningless single-letter variable names. And add comments!
One possible algorithm is:
Get the parent of the node to delete
Get the right-most node of the left subtree, or the leftmost node of the right subtree
Remove the node to delete and replace it with the node you found
Rebalance the tree
...or, if you want to hack up this stuff so it's right, I'd start looking at the
if (x != null){
Node tmp = getParent(t,x);
tmp = getParent(t,y);
}
part, because that's clearly wrong.
I'll have to side with Anon and go for the rewrite. The null pointers come from your getParent function (which explicitly returns nulls along other things). So I would start there and fix the function(s) so that they return one thing and one thing only at the end of the function.
Here is the complete Implementation of Binary Search Tree In Java
insert,search,countNodes,traversal,delete,empty,maximum & minimum node,find parent node,print all leaf node, get level,get height, get depth,print left view, mirror view
import java.util.NoSuchElementException;
import java.util.Scanner;
import org.junit.experimental.max.MaxCore;
class BSTNode {
BSTNode left = null;
BSTNode rigth = null;
int data = 0;
public BSTNode() {
super();
}
public BSTNode(int data) {
this.left = null;
this.rigth = null;
this.data = data;
}
#Override
public String toString() {
return "BSTNode [left=" + left + ", rigth=" + rigth + ", data=" + data + "]";
}
}
class BinarySearchTree {
BSTNode root = null;
public BinarySearchTree() {
}
public void insert(int data) {
BSTNode node = new BSTNode(data);
if (root == null) {
root = node;
return;
}
BSTNode currentNode = root;
BSTNode parentNode = null;
while (true) {
parentNode = currentNode;
if (currentNode.data == data)
throw new IllegalArgumentException("Duplicates nodes note allowed in Binary Search Tree");
if (currentNode.data > data) {
currentNode = currentNode.left;
if (currentNode == null) {
parentNode.left = node;
return;
}
} else {
currentNode = currentNode.rigth;
if (currentNode == null) {
parentNode.rigth = node;
return;
}
}
}
}
public int countNodes() {
return countNodes(root);
}
private int countNodes(BSTNode node) {
if (node == null) {
return 0;
} else {
int count = 1;
count += countNodes(node.left);
count += countNodes(node.rigth);
return count;
}
}
public boolean searchNode(int data) {
if (empty())
return empty();
return searchNode(data, root);
}
public boolean searchNode(int data, BSTNode node) {
if (node != null) {
if (node.data == data)
return true;
else if (node.data > data)
return searchNode(data, node.left);
else if (node.data < data)
return searchNode(data, node.rigth);
}
return false;
}
public boolean delete(int data) {
if (empty())
throw new NoSuchElementException("Tree is Empty");
BSTNode currentNode = root;
BSTNode parentNode = root;
boolean isLeftChild = false;
while (currentNode.data != data) {
parentNode = currentNode;
if (currentNode.data > data) {
isLeftChild = true;
currentNode = currentNode.left;
} else if (currentNode.data < data) {
isLeftChild = false;
currentNode = currentNode.rigth;
}
if (currentNode == null)
return false;
}
// CASE 1: node with no child
if (currentNode.left == null && currentNode.rigth == null) {
if (currentNode == root)
root = null;
if (isLeftChild)
parentNode.left = null;
else
parentNode.rigth = null;
}
// CASE 2: if node with only one child
else if (currentNode.left != null && currentNode.rigth == null) {
if (root == currentNode) {
root = currentNode.left;
}
if (isLeftChild)
parentNode.left = currentNode.left;
else
parentNode.rigth = currentNode.left;
} else if (currentNode.rigth != null && currentNode.left == null) {
if (root == currentNode)
root = currentNode.rigth;
if (isLeftChild)
parentNode.left = currentNode.rigth;
else
parentNode.rigth = currentNode.rigth;
}
// CASE 3: node with two child
else if (currentNode.left != null && currentNode.rigth != null) {
// Now we have to find minimum element in rigth sub tree
// that is called successor
BSTNode successor = getSuccessor(currentNode);
if (currentNode == root)
root = successor;
if (isLeftChild)
parentNode.left = successor;
else
parentNode.rigth = successor;
successor.left = currentNode.left;
}
return true;
}
private BSTNode getSuccessor(BSTNode deleteNode) {
BSTNode successor = null;
BSTNode parentSuccessor = null;
BSTNode currentNode = deleteNode.left;
while (currentNode != null) {
parentSuccessor = successor;
successor = currentNode;
currentNode = currentNode.left;
}
if (successor != deleteNode.rigth) {
parentSuccessor.left = successor.left;
successor.rigth = deleteNode.rigth;
}
return successor;
}
public int nodeWithMinimumValue() {
return nodeWithMinimumValue(root);
}
private int nodeWithMinimumValue(BSTNode node) {
if (node.left != null)
return nodeWithMinimumValue(node.left);
return node.data;
}
public int nodewithMaximumValue() {
return nodewithMaximumValue(root);
}
private int nodewithMaximumValue(BSTNode node) {
if (node.rigth != null)
return nodewithMaximumValue(node.rigth);
return node.data;
}
public int parent(int data) {
return parent(root, data);
}
private int parent(BSTNode node, int data) {
if (empty())
throw new IllegalArgumentException("Empty");
if (root.data == data)
throw new IllegalArgumentException("No Parent node found");
BSTNode parent = null;
BSTNode current = node;
while (current.data != data) {
parent = current;
if (current.data > data)
current = current.left;
else
current = current.rigth;
if (current == null)
throw new IllegalArgumentException(data + " is not a node in tree");
}
return parent.data;
}
public int sibling(int data) {
return sibling(root, data);
}
private int sibling(BSTNode node, int data) {
if (empty())
throw new IllegalArgumentException("Empty");
if (root.data == data)
throw new IllegalArgumentException("No Parent node found");
BSTNode cureent = node;
BSTNode parent = null;
boolean isLeft = false;
while (cureent.data != data) {
parent = cureent;
if (cureent.data > data) {
cureent = cureent.left;
isLeft = true;
} else {
cureent = cureent.rigth;
isLeft = false;
}
if (cureent == null)
throw new IllegalArgumentException("No Parent node found");
}
if (isLeft) {
if (parent.rigth != null) {
return parent.rigth.data;
} else
throw new IllegalArgumentException("No Sibling is there");
} else {
if (parent.left != null)
return parent.left.data;
else
throw new IllegalArgumentException("No Sibling is there");
}
}
public void leafNodes() {
if (empty())
throw new IllegalArgumentException("Empty");
leafNode(root);
}
private void leafNode(BSTNode node) {
if (node == null)
return;
if (node.rigth == null && node.left == null)
System.out.print(node.data + " ");
leafNode(node.left);
leafNode(node.rigth);
}
public int level(int data) {
if (empty())
throw new IllegalArgumentException("Empty");
return level(root, data, 1);
}
private int level(BSTNode node, int data, int level) {
if (node == null)
return 0;
if (node.data == data)
return level;
int result = level(node.left, data, level + 1);
if (result != 0)
return result;
result = level(node.rigth, data, level + 1);
return result;
}
public int depth() {
return depth(root);
}
private int depth(BSTNode node) {
if (node == null)
return 0;
else
return 1 + Math.max(depth(node.left), depth(node.rigth));
}
public int height() {
return height(root);
}
private int height(BSTNode node) {
if (node == null)
return 0;
else
return 1 + Math.max(height(node.left), height(node.rigth));
}
public void leftView() {
leftView(root);
}
private void leftView(BSTNode node) {
if (node == null)
return;
int height = height(node);
for (int i = 1; i <= height; i++) {
printLeftView(node, i);
}
}
private boolean printLeftView(BSTNode node, int level) {
if (node == null)
return false;
if (level == 1) {
System.out.print(node.data + " ");
return true;
} else {
boolean left = printLeftView(node.left, level - 1);
if (left)
return true;
else
return printLeftView(node.rigth, level - 1);
}
}
public void mirroeView() {
BSTNode node = mirroeView(root);
preorder(node);
System.out.println();
inorder(node);
System.out.println();
postorder(node);
System.out.println();
}
private BSTNode mirroeView(BSTNode node) {
if (node == null || (node.left == null && node.rigth == null))
return node;
BSTNode temp = node.left;
node.left = node.rigth;
node.rigth = temp;
mirroeView(node.left);
mirroeView(node.rigth);
return node;
}
public void preorder() {
preorder(root);
}
private void preorder(BSTNode node) {
if (node != null) {
System.out.print(node.data + " ");
preorder(node.left);
preorder(node.rigth);
}
}
public void inorder() {
inorder(root);
}
private void inorder(BSTNode node) {
if (node != null) {
inorder(node.left);
System.out.print(node.data + " ");
inorder(node.rigth);
}
}
public void postorder() {
postorder(root);
}
private void postorder(BSTNode node) {
if (node != null) {
postorder(node.left);
postorder(node.rigth);
System.out.print(node.data + " ");
}
}
public boolean empty() {
return root == null;
}
}
public class BinarySearchTreeTest {
public static void main(String[] l) {
System.out.println("Weleome to Binary Search Tree");
Scanner scanner = new Scanner(System.in);
boolean yes = true;
BinarySearchTree tree = new BinarySearchTree();
do {
System.out.println("\n1. Insert");
System.out.println("2. Search Node");
System.out.println("3. Count Node");
System.out.println("4. Empty Status");
System.out.println("5. Delete Node");
System.out.println("6. Node with Minimum Value");
System.out.println("7. Node with Maximum Value");
System.out.println("8. Find Parent node");
System.out.println("9. Count no of links");
System.out.println("10. Get the sibling of any node");
System.out.println("11. Print all the leaf node");
System.out.println("12. Get the level of node");
System.out.println("13. Depth of the tree");
System.out.println("14. Height of Binary Tree");
System.out.println("15. Left View");
System.out.println("16. Mirror Image of Binary Tree");
System.out.println("Enter Your Choice :: ");
int choice = scanner.nextInt();
switch (choice) {
case 1:
try {
System.out.println("Enter Value");
tree.insert(scanner.nextInt());
} catch (Exception e) {
System.out.println(e.getMessage());
}
break;
case 2:
System.out.println("Enter the node");
System.out.println(tree.searchNode(scanner.nextInt()));
break;
case 3:
System.out.println(tree.countNodes());
break;
case 4:
System.out.println(tree.empty());
break;
case 5:
try {
System.out.println("Enter the node");
System.out.println(tree.delete(scanner.nextInt()));
} catch (Exception e) {
System.out.println(e.getMessage());
}
case 6:
try {
System.out.println(tree.nodeWithMinimumValue());
} catch (Exception e) {
System.out.println(e.getMessage());
}
break;
case 7:
try {
System.out.println(tree.nodewithMaximumValue());
} catch (Exception e) {
System.out.println(e.getMessage());
}
break;
case 8:
try {
System.out.println("Enter the node");
System.out.println(tree.parent(scanner.nextInt()));
} catch (Exception e) {
System.out.println(e.getMessage());
}
break;
case 9:
try {
System.out.println(tree.countNodes() - 1);
} catch (Exception e) {
System.out.println(e.getMessage());
}
break;
case 10:
try {
System.out.println("Enter the node");
System.out.println(tree.sibling(scanner.nextInt()));
} catch (Exception e) {
System.out.println(e.getMessage());
}
break;
case 11:
try {
tree.leafNodes();
} catch (Exception e) {
System.out.println(e.getMessage());
}
case 12:
try {
System.out.println("Enter the node");
System.out.println("Level is : " + tree.level(scanner.nextInt()));
} catch (Exception e) {
System.out.println(e.getMessage());
}
break;
case 13:
try {
System.out.println(tree.depth());
} catch (Exception e) {
System.out.println(e.getMessage());
}
break;
case 14:
try {
System.out.println(tree.height());
} catch (Exception e) {
System.out.println(e.getMessage());
}
break;
case 15:
try {
tree.leftView();
System.out.println();
} catch (Exception e) {
System.out.println(e.getMessage());
}
break;
case 16:
try {
tree.mirroeView();
} catch (Exception e) {
System.out.println(e.getMessage());
}
break;
default:
break;
}
tree.preorder();
System.out.println();
tree.inorder();
System.out.println();
tree.postorder();
} while (yes);
scanner.close();
}
}
As per my understanding following implementation done for binary search tree, kindly look
into that and let me know any feedback required
Insertion
InOrderTraversal
Search
Removal
Please take a look at the main method. so, Please provide your's feedback to improve further from my side.
public class BinarySearchTree {
private Node root;
public BinarySearchTree() {
root = null;
}
public BinarySearchTree(int rootData) {
root = new Node(rootData);
}
public void insertElement(int element,Node parent) {
Node temp = root;
if(parent!=null) temp = parent;
if(temp!=null) {
Node node = new Node(element);
if(element<temp.getData()) {
if(temp.getLeft()!=null)
insertElement(element, temp.getLeft());
else
temp.setLeft(node);
}else if(element>temp.getData()) {
if(temp.getRight()!=null)
insertElement(element, temp.getRight());
else
temp.setRight(node);
}
}
}
public void traverseInOrder() {
if(root!=null) {
traverse(root.getLeft());
System.out.println(root.getData());
traverse(root.getRight());
}
}
public void traverse(Node temp) {
if(temp!=null) {
traverse(temp.getLeft());
System.out.println(temp.getData());
traverse(temp.getRight());
}
}
public int searchElement(int element,Node node) {
Node temp = root;
if(node!=null) temp = node;
if(temp!=null) {
if(temp.getData()<element) {
if(temp.getRight()!=null)
return searchElement(element, temp.getRight());
}else if(temp.getData()>element) {
if(temp.getLeft()!=null)
return searchElement(element,temp.getLeft());
}else if(temp.getData()==element){
return temp.getData();
}
}
return -1;
}
public void remove(int element,Node node,Node predecer) {
Node temp = root;
if(node!=null) temp = node;
if(temp!=null) {
if(temp.getData()>element) {
remove(element, temp.getLeft(), temp);
}else if(temp.getData()<element) {
remove(element, temp.getRight(), temp);
}else if(element==temp.getData()) {
if(temp.getLeft()==null && temp.getRight()==null) {
if(predecer.getData()>temp.getData()) {
predecer.setLeft(null);
}else if(predecer.getData()<temp.getData()) {
predecer.setRight(null);
}
}else if(temp.getLeft()!=null && temp.getRight()==null) {
predecer.setRight(temp.getLeft());
}else if(temp.getLeft()==null && temp.getRight()!=null) {
predecer.setLeft(temp.getRight());
}else if(temp.getLeft()!=null && temp.getRight()!=null) {
Node leftMostElement = findMaximumLeft(temp.getLeft());
if(leftMostElement!=null) {
remove(leftMostElement.getData(), temp, temp);
temp.setData(leftMostElement.getData());
}
}
}
}
}
public Node findMaximumLeft(Node parent) {
Node temp = parent;
if(temp.getRight()!=null)
return findMaximumLeft(temp.getRight());
else
return temp;
}
public static void main(String[] args) {
BinarySearchTree bs = new BinarySearchTree(10);
bs.insertElement(29, null);
bs.insertElement(19, null);
bs.insertElement(209, null);
bs.insertElement(6, null);
bs.insertElement(7, null);
bs.insertElement(17, null);
bs.insertElement(37, null);
bs.insertElement(67, null);
bs.insertElement(-7, null);
bs.remove(6, null, null);
bs.traverseInOrder();}}