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Commit afc38dc

Browse files
inserted code for tress by Ds Guy
1 parent cd76485 commit afc38dc

12 files changed

+1331
-0
lines changed

‎src/dsGuy/AVLTree/AVLTree.java

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package dsGuy.AVLTree;
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import java.util.LinkedList;
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import java.util.Queue;
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import dsGuy.node.*;
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public class AVLTree {
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BinaryNode root;
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public BinaryNode getRoot() {
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return root;
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}
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// Constructor
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AVLTree() {
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root = null;
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}
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// Insert values in AVL Tree
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void insert(int value) {
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root = insert(root, value);
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}// end of method
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// Helper Method
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BinaryNode insert(BinaryNode currentNode, int value) {
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// THIS ELSE_IF BLOCK IS BST CONDITION
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if (currentNode == null) {
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System.out.println("Successfully inserted " + value + " in AVL Tree");
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return createNewNode(value);
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} else if (value <= currentNode.getValue()) {
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currentNode.setLeft(insert(currentNode.getLeft(), value));
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} else {
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currentNode.setRight(insert(currentNode.getRight(), value));
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}
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// THIS IS WHERE WE WILL DO AVL SPECIFIC WORK
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int balance = checkBalance(currentNode.getLeft(), currentNode.getRight());
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if (balance > 1) {
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if (checkBalance(currentNode.getLeft().getLeft(), currentNode.getLeft().getRight()) > 0) {
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currentNode = rightRotate(currentNode);// LL Condition
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} else {
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currentNode.setLeft(leftRotate(currentNode.getLeft())); // LR Condition
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currentNode = rightRotate(currentNode);
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}
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} else if (balance < -1) {
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if (checkBalance(currentNode.getRight().getRight(), currentNode.getRight().getLeft()) > 0) {
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currentNode = leftRotate(currentNode);// RR Condition
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} else {
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currentNode.setRight(rightRotate(currentNode.getRight()));// RL Condition
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currentNode = leftRotate(currentNode);
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}
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}
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if (currentNode.getLeft() != null) {
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currentNode.getLeft().setHeight(calculateHeight(currentNode.getLeft()));
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}
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if (currentNode.getRight() != null) {
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currentNode.getRight().setHeight(calculateHeight(currentNode.getRight()));
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}
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currentNode.setHeight(calculateHeight(currentNode));
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return currentNode;
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}// end of method
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// Helper Method
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private BinaryNode leftRotate(BinaryNode currentNode) {
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BinaryNode newRoot = currentNode.getRight();
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currentNode.setRight(currentNode.getRight().getLeft());
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newRoot.setLeft(currentNode);
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currentNode.setHeight(calculateHeight(currentNode));
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newRoot.setHeight(calculateHeight(newRoot));
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return newRoot;
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}// end of method
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// Helper Method
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private BinaryNode rightRotate(BinaryNode currentNode) {
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BinaryNode newRoot = currentNode.getLeft();
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currentNode.setLeft(currentNode.getLeft().getRight());
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newRoot.setRight(currentNode);
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currentNode.setHeight(calculateHeight(currentNode));
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newRoot.setHeight(calculateHeight(newRoot));
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return newRoot;
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}// end of method
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// Helper Method
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private int checkBalance(BinaryNode rootLeft, BinaryNode rootRight) {
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if((rootLeft == null) && (rootRight == null)) { //if current node is a leaf node then no need to check balance of its children
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return 0;
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}else if (rootLeft == null) {
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return -1 * (rootRight.getHeight() + 1); // if left node node is not there then simply return right node's
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// height + 1
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// we need to make it -1 because blank height is considered
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// having height as '-1'
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} else if (rootRight == null) {
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return rootLeft.getHeight() + 1;
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} else {
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return rootLeft.getHeight() - rootRight.getHeight(); // +1 is not required, as both right and left child
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// exits and 1 gets nullified
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}
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}// end of method
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// Calculate height of Node
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private int calculateHeight(BinaryNode currentNode) {
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if (currentNode == null) {
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return 0;
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}
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return 1 + Math.max((currentNode.getLeft() != null ? currentNode.getLeft().getHeight() : -1),
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(currentNode.getRight() != null ? currentNode.getRight().getHeight() : -1));
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}// end of method
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// creates a new blank new node
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public BinaryNode createNewNode(int value) {
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BinaryNode node = new BinaryNode();
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node.setValue(value);
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node.setHeight(0);// Since this is a leaf node, its height is 0
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return node;
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}// end of method
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// Level order traversal of BST
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void levelOrderTraversal() {
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Queue<BinaryNode> queue = new LinkedList<BinaryNode>();
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queue.add(root);
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System.out.println("Printing Level order traversal of AVL Tree...");
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if (root == null) {
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System.out.println("Tree does not exists !");
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return;
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}
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while (!queue.isEmpty()) {
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BinaryNode presentNode = queue.remove();
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System.out.print(presentNode.getValue() + " ");
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if (presentNode.getLeft() != null)
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queue.add(presentNode.getLeft());
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if (presentNode.getRight() != null)
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queue.add(presentNode.getRight());
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}
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}// end of method
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// Deleting a node from BST
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public void deleteNodeOfBST(int value) {
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System.out.println("Deleting " + value + " from AVL Tree ...");
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root = deleteNodeOfBST(root, value);
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}
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// Helper Method for delete
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public BinaryNode deleteNodeOfBST(BinaryNode currentNode, int value) {
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// THIS ELSE_IF BLOCK IS BST CONDITION
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if (currentNode == null)
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return null;
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if (value < currentNode.getValue()) {
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currentNode.setLeft(deleteNodeOfBST(currentNode.getLeft(), value));
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} else if (value > currentNode.getValue()) {
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currentNode.setRight(deleteNodeOfBST(currentNode.getRight(), value));
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} else { // If currentNode is the node to be deleted
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//System.out.println("currentNode is the node to be deleted");
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if (currentNode.getLeft() != null && currentNode.getRight() != null) { // if nodeToBeDeleted have both children
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BinaryNode temp = currentNode;
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BinaryNode minNodeForRight = minimumElement(temp.getRight());// Finding minimum element from right subtree
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currentNode.setValue(minNodeForRight.getValue()); // Replacing current node with minimum node from right subtree
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deleteNodeOfBST(currentNode.getRight(), minNodeForRight.getValue());// Deleting minimum node from right now
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} else if (currentNode.getLeft() != null) {// if nodeToBeDeleted has only left child
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currentNode = currentNode.getLeft();
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} else if (currentNode.getRight() != null) {// if nodeToBeDeleted has only right child
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currentNode = currentNode.getRight();
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} else { // if nodeToBeDeleted do not have child (Leaf node)
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//System.out.println("This node is leaf node");
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currentNode = null;
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}
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return currentNode;// if it is a leaf node,then no need to do balancing for this node, do only for its ancestors
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}
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// THIS IS WHERE WE WILL DO AVL SPECIFIC WORK
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int balance = checkBalance(currentNode.getLeft(), currentNode.getRight());
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if (balance > 1) {
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if (checkBalance(currentNode.getLeft().getLeft(), currentNode.getLeft().getRight()) > 0) {
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currentNode = rightRotate(currentNode);// LL Condition
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} else {
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currentNode.setLeft(leftRotate(currentNode.getLeft())); // LR Condition
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currentNode = rightRotate(currentNode);
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}
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} else if (balance < -1) {
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if (checkBalance(currentNode.getRight().getRight(), currentNode.getRight().getLeft()) > 0) {
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currentNode = leftRotate(currentNode);// RR Condition
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} else {
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currentNode.setRight(rightRotate(currentNode.getRight()));// RL Condition
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currentNode = leftRotate(currentNode);
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}
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}
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if (currentNode.getLeft() != null) {
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currentNode.getLeft().setHeight(calculateHeight(currentNode.getLeft()));
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}
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if (currentNode.getRight() != null) {
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currentNode.getRight().setHeight(calculateHeight(currentNode.getRight()));
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}
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currentNode.setHeight(calculateHeight(currentNode));
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return currentNode;
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}// end of method
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// Get minimum element in binary search tree
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public static BinaryNode minimumElement(BinaryNode root) {
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if (root.getLeft() == null)
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return root;
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else {
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return minimumElement(root.getLeft());
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}
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}// end of method
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void printTreeGraphically() {
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Queue<BinaryNode> queue = new LinkedList<BinaryNode>();
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Queue<Integer> level = new LinkedList<Integer>();
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int CurrentLevel = 1;
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boolean previousLevelWasAllNull = false;
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queue.add(root);
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level.add(1);
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System.out.println("\nPrinting Level order traversal of Tree...");
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if(root == null) {
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System.out.println("Tree does not exists !");
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return;
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}
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while (!queue.isEmpty()) {
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if(CurrentLevel == level.peek()) { //if we are in the same level
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if(queue.peek()==null) {
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queue.add(null);level.add(CurrentLevel+1);
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}else {
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queue.add(queue.peek().getLeft());level.add(CurrentLevel+1);
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queue.add(queue.peek().getRight());level.add(CurrentLevel+1);
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previousLevelWasAllNull = false;
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}
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System.out.print(queue.remove() + " ");level.remove();
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}else { //level has changed
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System.out.println("\n");
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CurrentLevel++;
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if(previousLevelWasAllNull == true) {
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break;
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}
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previousLevelWasAllNull = true;
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}
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}//end of loop
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}//end of method
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}// end of class

‎src/dsGuy/AVLTree/Main.java

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package dsGuy.AVLTree;
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public class Main {
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public static void main(String[] args) {
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// Constructor
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AVLTree tree = new AVLTree();
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// Insert values in AVL Tree
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tree.insert(30);
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tree.insert(10);
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tree.insert(5);
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tree.insert(3);
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tree.insert(4);
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tree.insert(50);
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tree.insert(65);
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tree.insert(1);
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tree.levelOrderTraversal();
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tree.printTreeGraphically();
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tree.deleteNodeOfBST(5);//LL Condition
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tree.printTreeGraphically();
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tree.insert(2);
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tree.printTreeGraphically();
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tree.deleteNodeOfBST(4);//LR Condition
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tree.printTreeGraphically();
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tree.insert(20);
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tree.deleteNodeOfBST(65);//RR Condition
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tree.printTreeGraphically();
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tree.insert(40);
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tree.deleteNodeOfBST(20);//RL Condition
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tree.printTreeGraphically();
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}// end of method
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}// end of class

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