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Last active Nov 12, 2018

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CSC-220 Modified LinkedList Code
package chapter24;
public class MyLinkedList<E> implements MyList<E> {
private static class Node<E> {
E element;
Node<E> next;
public Node(E element) {
this(element, null);
}
public Node(E element, Node<E> next) {
this.element = element;
this.next = next;
}
}
private Node<E> head, tail;
private int size = 0; // Number of elements in the list
/** Create an empty list */
public MyLinkedList() {
}
/** Create a list from an array of objects */
public MyLinkedList(E[] objects) {
for (int i = 0; i < objects.length; i++)
add(objects[i]);
}
/** Return the head element in the list */
public E getFirst() {
if (size == 0) {
return null;
}
else {
return head.element;
}
}
/** Return the last element in the list */
public E getLast() {
if (size == 0) {
return null;
}
else {
return tail.element;
}
}
/** Add an element to the beginning of the list */
public void addFirst(E e) {
Node<E> newNode = new Node<>(e); // Create a new node
newNode.next = head; // link the new node with the head
head = newNode; // head points to the new node
size++; // Increase list size
if (tail == null) // the new node is the only node in list
tail = head;
}
/** Add an element to the end of the list */
public void addLast(E e) {
Node<E> newNode = new Node<>(e); // Create a new for element e
if (tail == null) {
head = tail = newNode; // The new node is the only node in list
}
else {
tail.next = newNode; // Link the new with the last node
tail = newNode; // tail now points to the last node
}
size++; // Increase size
}
@Override /**
* Add a new element at the specified index in this list. The index of the head
* element is 0
*/
public void add(int index, E e) {
if (index == 0) {
addFirst(e);
}
else if (index >= size) {
addLast(e);
}
else {
Node<E> current = head;
for (int i = 1; i < index; i++) {
current = current.next;
}
Node<E> temp = current.next;
current.next = new Node<>(e);
(current.next).next = temp;
size++;
}
}
/**
* Remove the head node and return the object that is contained in the removed
* node.
*/
public E removeFirst() {
if (size == 0) {
return null;
}
else {
E temp = head.element;
head = head.next;
size--;
if (head == null) {
tail = null;
}
return temp;
}
}
/**
* Remove the last node and return the object that is contained in the removed
* node.
*/
public E removeLast() {
if (size == 0) {
return null;
}
else if (size == 1) {
E temp = head.element;
head = tail = null;
size = 0;
return temp;
}
else {
Node<E> current = head;
for (int i = 0; i < size - 2; i++) {
current = current.next;
}
E temp = tail.element;
tail = current;
tail.next = null;
size--;
return temp;
}
}
@Override /**
* Remove the element at the specified position in this list. Return the element
* that was removed from the list.
*/
public E remove(int index) {
if (index < 0 || index >= size) {
return null;
}
else if (index == 0) {
return removeFirst();
}
else if (index == size - 1) {
return removeLast();
}
else {
Node<E> previous = head;
for (int i = 1; i < index; i++) {
previous = previous.next;
}
Node<E> current = previous.next;
previous.next = current.next;
size--;
return current.element;
}
}
@Override /** Override toString() to return elements in the list */
public String toString() {
StringBuilder result = new StringBuilder("[");
Node<E> current = head;
for (int i = 0; i < size; i++) {
result.append(current.element);
current = current.next;
if (current != null) {
result.append(", "); // Separate two elements with a comma
}
else {
result.append("]"); // Insert the closing ] in the string
}
}
return result.toString();
}
@Override /** Clear the list */
public void clear() {
size = 0;
head = tail = null;
}
@Override /** Return true if this list contains the element e */
public boolean contains(Object e) {
// Left as an exercise
return true;
}
@Override /** Return the element at the specified index */
public E get(int index) {
// Left as an exercise
return null;
}
@Override /**
* Return the index of the head matching element in this list. Return -1 if no
* match.
*/
public int indexOf(Object e) {
// Left as an exercise
return 0;
}
@Override /**
* Return the index of the last matching element in this list. Return -1 if no
* match.
*/
public int lastIndexOf(E e) {
// Left as an exercise
return 0;
}
@Override /**
* Replace the element at the specified position in this list with the specified
* element.
*/
public E set(int index, E e) {
// Left as an exercise
return null;
}
@Override /** Return the number of elements in this list */
public int size() {
return size;
}
@Override /** Override iterator() defined in Iterable */
public java.util.Iterator<E> iterator() {
return new LinkedListIterator();
}
private class LinkedListIterator implements java.util.Iterator<E> {
private Node<E> current = head; // Current index
@Override
public boolean hasNext() {
return (current != null);
}
@Override
public E next() {
E e = current.element;
current = current.next;
return e;
}
@Override
public void remove() {
// Left as an exercise
}
}
}
// Test Program to check ArrayList vs LinkList Performance
package chapter24;
public class TestMyList {
/** Main method */
public static void main(String[] args) {
// Create a list for strings
long start = System.nanoTime();
MyList<String> list = new MyLinkedList2<>();
//MyList<String> list = new MyArrayList<String>();
// Add elements to the list
list.add("America"); // Add it to the list
System.out.println("(1) " + list);
for (int i=0; i < 10000; i++) {
list.add(0, "USAUSAUSA");
}
for (int i=0; i < 10000; i++) {
list.remove(0);
}
list.add(0, "Canada"); // Add it to the beginning of the list
//System.out.println("(2) " + list);
list.add("Russia"); // Add it to the end of the list
//System.out.println("(3) " + list);
list.add("France"); // Add it to the end of the list
//System.out.println("(4) " + list);
list.add(2, "Germany"); // Add it to the list at index 2
//System.out.println("(5) " + list);
list.add(5, "Norway"); // Add it to the list at index 5
//System.out.println("(6) " + list);
list.add(0, "Poland"); // Same as list.addFirst("Poland")
//System.out.println("(7) " + list);
// Remove elements from the list
list.remove(0); // Same as list.remove("Australia") in this case
//System.out.println("(8) " + list);
list.remove(2); // Remove the element at index 2
//System.out.println("(9) " + list);
list.remove(list.size() - 1); // Remove the last element
//System.out.print("(10) " + list + "\n(11) ");
//for (String s : list)
// System.out.print(s.toUpperCase() + " ");
long end = System.nanoTime();
System.out.printf("%,d", end - start);
//list.clear();
//System.out.println("\nAfter clearing the list, the list size is "
// + list.size());
}
}
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