DLL Update

DLL Update

Author: careermonk

bin/chapter3linkedlists/DLLNode.class

@@ -0,0 +1,57 @@
+/*Copyright (c) Dec 21, 2014 CareerMonk Publications and others.
+ * E-Mail           	: info@careermonk.com 
+ * Creation Date    	: 2015-01-10 06:15:46 
+ * Last modification	: 2006-05-31 
+               by		: Narasimha Karumanchi 
+ * File Name			: DLLNode.java
+ * Book Title			: Data Structures And Algorithms Made In Java
+ * Warranty         	: This software is provided "as is" without any 
+ * 							warranty; without even the implied warranty of 
+ * 							merchantability or fitness for a particular purpose. 
+ * 
+ */
+
+
+package chapter3linkedlists;
+
+public class DLLNode {
+	public int data;
+	public DLLNode prev;
+	public DLLNode next;
+
+	public DLLNode(int data) {
+		this.data = data;
+		prev = null;
+		next = null;
+	} 
+	
+	public DLLNode(int data, DLLNode prev, DLLNode next) {
+		this.data = data;
+		this.prev = prev;
+		this.next = next;
+	}
+	
+	public int getData() {
+		return data;
+	}
+	
+	public void setData(int data) {
+		this.data = data;
+	}
+	
+	public DLLNode getPrev() {
+		return prev;
+	} 
+
+	public DLLNode getNext() {
+		return next;
+	} 
+
+	public void setPrev(DLLNode where) {
+		prev = where;
+	} 
+
+	public void setNext(DLLNode where) {
+		next = where;
+	} 
+} 

bin/chapter3linkedlists/DoublyLinkedList.class

@@ -0,0 +1,211 @@
+/*Copyright (c) Dec 21, 2014 CareerMonk Publications and others.
+ * E-Mail           	: info@careermonk.com 
+ * Creation Date    	: 2015-01-10 06:15:46 
+ * Last modification	: 2006-05-31 
+               by		: Narasimha Karumanchi 
+ * File Name			: DoublyLinkedList.java
+ * Book Title			: Data Structures And Algorithms Made In Java
+ * Warranty         	: This software is provided "as is" without any 
+ * 							warranty; without even the implied warranty of 
+ * 							merchantability or fitness for a particular purpose. 
+ * 
+ */
+
+package chapter3linkedlists;
+
+public class DoublyLinkedList{
+	// properties
+	private DLLNode head;
+	private DLLNode tail;
+	private int length;
+
+	// Create a new empty list.
+	public DoublyLinkedList() {
+		head = new DLLNode(Integer.MIN_VALUE,null,null);
+		tail = new DLLNode(Integer.MIN_VALUE, head, null);
+		head.setNext(tail);
+		length = 0;
+	} 
+
+	// Get the value at a given position.
+	public int get(int position) {
+		return Integer.MIN_VALUE;
+	}
+
+	// Find the position of the head value that is equal to a given value.
+	// The equals method us used to determine equality.
+	public int getPosition(int data) {
+		// go looking for the data
+		DLLNode temp = head;
+		int pos = 0;
+		while (temp != null) {
+			if (temp.getData() == data) {
+				// return the position if found
+				return pos;
+			}
+			pos += 1;
+			temp = temp.getNext();
+		}
+		// else return -1
+		return Integer.MIN_VALUE;
+	} 
+
+	// Return the current length of the DLL.
+	public int length() {
+		return length;
+	}
+
+	// Add a new value to the front of the list.
+	public void insert(int newValue) {
+		DLLNode newNode = new DLLNode(newValue,head,head.getNext());
+		newNode.getNext().setPrev(newNode);
+		head.setNext(newNode);
+		length += 1;
+	} 
+
+	// Add a new value to the list at a given position.
+	// All values at that position to the end move over to make room.
+	public void insert(int data, int position) {
+		// fix the position
+		if (position < 0) {
+			position = 0;
+		}
+		if (position > length) {
+			position = length;
+		}
+
+		// if the list is empty, make it be the only element
+		if (head == null) {
+			head = new DLLNode(data);
+			tail = head;
+		}
+		// if adding at the front of the list...
+		else if (position == 0) {
+			DLLNode temp = new DLLNode(data);
+			temp.next = head;
+			head = temp;
+		}
+		// else find the correct position and insert
+		else {
+			DLLNode temp = head;
+			for (int i=1; i<position; i+=1) {
+				temp = temp.getNext();
+			}
+			DLLNode newNode = new DLLNode(data);
+			newNode.next = temp.next;
+			newNode.prev = temp;
+			newNode.next.prev = newNode;
+			temp.next = newNode;
+		}
+		// the list is now one value longer
+		length += 1;
+	} 
+	
+	// Add a new value to the rear of the list.
+	public void insertTail(int newValue) {
+		DLLNode newNode = new DLLNode(newValue,tail.getPrev(),tail);
+		newNode.getPrev().setNext(newNode);
+		tail.setPrev(newNode);
+		length += 1;
+	}
+
+	// Remove the value at a given position.
+	// If the position is less than 0, remove the value at position 0.
+	// If the position is greater than 0, remove the value at the last position.
+	public void remove(int position) {
+		// fix position
+		if (position < 0) {
+			position = 0;
+		}
+		
+		if (position >= length) {
+			position = length-1;
+		}
+		
+		// if nothing in the list, do nothing
+		if (head == null)
+			return;
+		
+		// if removing the head element...
+		if (position == 0) {
+			head = head.getNext();
+			if (head == null)
+				tail = null;
+		}
+		// else advance to the correct position and remove
+		else {
+			DLLNode temp = head;
+			for (int i=1; i<position; i+=1) {
+				temp = temp.getNext();
+			}
+			temp.getNext().setPrev(temp.getPrev());
+			temp.getPrev().setNext(temp.getNext());
+		}
+		// reduce the length of the list
+		length -= 1;
+	}
+	
+	// Remove a node matching the specified node from the list.  
+	// Use equals() instead of == to test for a matched node.
+	public synchronized void removeMatched(DLLNode node) {
+		if (head == null) 
+			return;
+		if (node.equals(head)) { 
+			head = head.getNext(); 
+			if (head == null)
+				tail = null;
+			return;
+		}
+		DLLNode p = head;
+		while(p != null) {
+			if (node.equals(p)) {
+				p.prev.next = p.next;
+				p.next.prev = p.prev;
+				return;
+			}
+		}
+	}
+	
+	// Remove the head value from the list. If the list is empty, do nothing.
+	public int removeHead() {
+		if (length == 0)
+		    return Integer.MIN_VALUE;
+		DLLNode save = head.getNext();
+		head.setNext(save.getNext());
+		save.getNext().setPrev(head);
+		length -= 1;
+		return save.getData();
+	} 
+
+	// Remove the tail value from the list. If the list is empty, do nothing.
+	public int removeTail() {
+		if (length == 0)
+			return Integer.MIN_VALUE;
+		DLLNode save = tail.getPrev();
+		tail.setPrev(save.getPrev());
+		save.getPrev().setNext(tail);
+		length -= 1;
+		return save.getData();
+	} 
+
+	// Return a string representation of this collection, in the form: ["str1","str2",...].
+	public String toString() {
+		String result = "[]";
+		if (length == 0)
+			return result;
+		result = "[" + head.getNext().getData();
+		DLLNode temp = head.getNext().getNext();
+		while (temp != tail) {
+			result += "," + temp.getData();
+			temp =  temp.getNext();
+		}
+		return result + "]";
+	}	
+	
+	// Remove everything from the DLL.
+	public void clearList(){
+		head = null;
+		tail = null;
+		length = 0;
+	}
+} 

bin/chapter3linkedlists/LinkedList.class

@@ -201,4 +201,10 @@ public int getPosition(int data) {
 		// else return -1
 		return Integer.MIN_VALUE;
 	}
+	
+	// Remove everything from the list.
+	public void clearList(){
+		head = null;
+		length = 0;
+	}
 }

bin/chapter3linkedlists/ListNode.class

@@ -23,9 +23,9 @@ public ListNode(){
 	}
 
 	// Creates a node storing the specified data.
-	public ListNode (int elem){
+	public ListNode (int data){
 		next = null;
-		data = elem;
+		this.data = data;
 	}
 
 	// Returns the node that follows this one.