Updates

Updates

Author: careermonk

bin/chapter3linkedlists/LinkedList.class

@@ -0,0 +1,204 @@
+/*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			: LinkedList.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 LinkedList {
+	// This class has a default constructor: 
+	public LinkedList() {
+		length = 0;
+	}
+
+	// This is the only field of the class.  It holds the head of the list 
+	ListNode head;
+	
+	// Length of the linked list
+	private int length = 0;
+
+	// Return the first node in the list 
+	public synchronized ListNode getHead() { 
+		return head; 
+	}
+
+	// Insert a node at the beginning of the list 
+	public synchronized void insertAtBegin(ListNode node) {
+		node.setNext(head);
+		head = node;
+		length ++;
+	}
+
+	// Insert a node at the end of the list 
+	public synchronized void insertAtEnd(ListNode node) {
+		if (head == null) 
+			head = node;
+		else {
+			ListNode p, q;
+			for(p = head; (q = p.getNext()) != null; p = q);
+				p.setNext(node);
+		}
+		length ++;
+	}
+	
+	// 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 ListNode(data);
+		}
+		// if adding at the front of the list...
+		else if (position == 0) {
+			ListNode temp = new ListNode(data);
+			temp.next = head;
+			head = temp;
+		}
+		// else find the correct position and insert
+		else {
+			ListNode temp = head;
+			for (int i=1; i<position; i+=1) {
+				temp = temp.getNext();
+			}
+			ListNode newNode = new ListNode(data);
+			newNode.next = temp.next;
+			temp.setNext(newNode);
+		}
+		// the list is now one value longer
+		length += 1;
+	} 
+	
+	// Remove and return the node at the head of the list 
+	public synchronized ListNode removeFromBegin() {
+		ListNode node = head;
+		if (node != null) {
+			head = node.getNext();
+			node.setNext(null);
+		}
+		return node;
+	}
+
+	// Remove and return the node at the end of the list 
+	public synchronized ListNode removeFromEnd() {
+		if (head == null) 
+			return null;
+		ListNode p = head, q = null, next = head.getNext();
+		if (next == null) {
+			head = null;
+			return p;
+		}
+		while((next = p.getNext()) != null) { 
+			q = p; 
+			p = next;
+		}
+		q.setNext(null);
+		return p;
+	}
+
+	// Remove a node matching the specified node from the list.  
+	// Use equals() instead of == to test for a matched node.
+	public synchronized void removeMatched(ListNode node) {
+		if (head == null) 
+			return;
+		if (node.equals(head)) { 
+			head = head.getNext(); 
+			return;
+		}
+		ListNode p = head, q = null;
+		while((q = p.getNext()) != null) {
+			if (node.equals(q)) {
+				p.setNext(q.getNext());
+				return;
+			}
+			p = q;
+		}
+	}
+	
+	// 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();
+		}
+
+		// else advance to the correct position and remove
+		else {
+			ListNode temp = head;
+			for (int i=1; i<position; i+=1) {
+				temp = temp.getNext();
+			}
+			temp.setNext(temp.getNext().getNext());
+		}
+		// reduce the length of the list
+		length -= 1;
+	}
+	
+	// Return a string representation of this collection, in the form ["str1","str2",...].
+	public String toString() {
+		String result = "[";
+		if (head == null) {
+			return result+"]";
+		}
+		result = result + head.getData();
+		ListNode temp = head.getNext();;
+		while (temp != null) {
+			result = result + "," + temp.getData();
+			temp = temp.getNext();
+		}
+		return result + "]";
+	}
+	
+	// Return the current length of the list.
+	public int length() {
+		return length;
+	}
+	
+	// Find the position of the first 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
+		ListNode 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;
+	}
+}