First commit

Author: thewillyhuman

.project

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+<?xml version="1.0" encoding="UTF-8"?>
+<projectDescription>
+	<name>AlgorithmsAndDataStructures</name>
+	<comment>Project AlgorithmsAndDataStructures created by Buildship.</comment>
+	<projects>
+	</projects>
+	<buildSpec>
+		<buildCommand>
+			<name>org.eclipse.jdt.core.javabuilder</name>
+			<arguments>
+			</arguments>
+		</buildCommand>
+		<buildCommand>
+			<name>org.eclipse.buildship.core.gradleprojectbuilder</name>
+			<arguments>
+			</arguments>
+		</buildCommand>
+	</buildSpec>
+	<natures>
+		<nature>org.eclipse.jdt.core.javanature</nature>
+		<nature>org.eclipse.buildship.core.gradleprojectnature</nature>
+	</natures>
+</projectDescription>

AVLTree/AVLNode.java

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+package AVLTree;
+
+
+/**
+ * Represents an AVL leave a an AVLTree.
+ * 
+ * @author Guillermo Facundo Colunga
+ * @version 2.1
+ * @param <T> Type of data that the AVLNode will contain.
+ */
+public class AVLNode<T extends Comparable<T>> {
+
+	private T element;
+	private AVLNode<T> left, right;
+	private int height;
+
+	/**
+	 * AVLNode Constructor. Only requires an element for the current AVLNode.
+	 * The left child and the right child will be set to null.
+	 * 
+	 * @param element to be set in the current AVLNode.
+	 * @throws Exception if element is null.
+	 */
+	public AVLNode( T element ) {
+		element( element );
+		left( null );
+		right( null );
+	}
+
+	/**
+	 * AVLNode Constructor. Requires the element for the current node, the
+	 * AVLNode of the left and the one for the right.
+	 * 
+	 * @param element for the current node
+	 * @param left AVLNode
+	 * @param right AVLNode
+	 * @throws Exception Exception if element, left or right is null.
+	 */
+	public AVLNode( T element, AVLNode<T> left, AVLNode<T> right ) {
+		element( element );
+		left( left );
+		right( right );
+	}
+
+	/**
+	 * Returns the actual value of the node. Notice that if the current value is
+	 * null will return null.
+	 * 
+	 * @return the value of the node. In other words the element that the node
+	 *         contains.
+	 */
+	public T element() {
+		return this.element;
+	}
+
+	/**
+	 * Sets the value of the node. Because of the implementation this method
+	 * will accept null values.
+	 * 
+	 * @param element to be set.
+	 */
+	public void element( T element ) {
+		this.element = element;
+	}
+
+	/**
+	 * Return the height of the subtree starting at the node.
+	 * 
+	 * @return the height as an Integer.
+	 */
+	public int height() {
+		updateHeight();
+		return this.height;
+	}
+
+	/**
+	 * Setter for the height property.
+	 * 
+	 * @param height to be set as new in the node.
+	 */
+	public void height( int height ) {
+		if (height < 0)
+			throw new IllegalArgumentException( "The height cannot be negative" );
+		this.height = height;
+	}
+
+	/**
+	 * Returns the AVLNode that is placed at the left. So its value is less than
+	 * the actual node. If there is no left child will return null.
+	 * 
+	 * @return the AVLNode that is placed at the left. Null if there isn't.
+	 */
+	public AVLNode<T> left() {
+		return this.left;
+	}
+
+	/**
+	 * Sets the AVLNode that is placed at the left. Because of the
+	 * implementation this method will accept null values.
+	 * 
+	 * @param left the node to be set.
+	 */
+	public void left( AVLNode<T> left ) {
+		this.left = left;
+	}
+
+	/**
+	 * Returns the AVLNode that is placed at the right. So its value is grater
+	 * than the actual node. If there is no left child will return null.
+	 * 
+	 * @return the AVLNode that is placed at the right. Null if there isn't.
+	 */
+	public AVLNode<T> right() {
+		return this.right;
+	}
+
+	/**
+	 * Sets the AVLNode that is placed at the left. Because of the
+	 * implementation this method will accept null values.
+	 * 
+	 * @param right the node to be set.
+	 */
+	public void right( AVLNode<T> right ) {
+		this.right = right;
+	}
+
+	/**
+	 * toString default method. Returns as an String the value of the element.
+	 * 
+	 * @return the value of the node.
+	 */
+	@Override public String toString() {
+		return this.element().toString() + "(" + balance() + ")";
+	}
+
+	/**
+	 * Prints the value of the toString method.
+	 */
+	public void print() {
+		System.out.println( this.toString() );
+	}
+
+	/**
+	 * Updates the height of the tree from a given root or node.
+	 */
+	protected void updateHeight() {
+		// If the node doesn't have children, its height is just 0
+		if (left() == null && right() == null)
+			height( 0 );
+
+		// If it has a child on one side, its height is its child's height plus
+		// one
+		else if (left() != null && right() == null)
+			height( 1 + left().height() );
+
+		else if (left() == null && right() != null)
+			height( 1 + right().height() );
+
+		// If it has one child on each side, its height will be the greatest of
+		// its childrens's height plus one
+		else if (left().height() > right().height())
+			height( 1 + left().height() );
+		else
+			height( 1 + right().height() );
+	}
+
+	/**
+	 * Calculates the balance factor of the node.
+	 * 
+	 * @return the balance factor of the node.
+	 */
+	public int balance() {
+		return calculateBalance();
+	}
+
+	/**
+	 * By means of the height returns the BF of the node. Three cases, the node
+	 * has no subtrees, has one subtree or has two subtrees.
+	 * 
+	 * @return
+	 */
+	private int calculateBalance() {
+
+		// If the node doesn't have children, its BF is just 0
+		if (left() == null && right() == null)
+			return 0;
+		// If it has a child on one side
+		else if (right() == null)
+			return -1 - left().height();
+		else if (left() == null && right() != null)
+			return 1 + right().height();
+		// If it has one child on each side
+		else
+			return ( right().height() - left().height() );
+	}
+}