ArrayQueue.java

public class ArrayQueue implements QueueInterface {

// Do not add new instance variables. private T[] backingArray; private int front; private int size;

/** * Constructs a new ArrayQueue. */ public ArrayQueue() {

}

/** * Dequeue from the front of the queue. * * Do not shrink the backing array. * If the queue becomes empty as a result of this call, you should * explicitly reset front to 0. * * You should replace any spots that you dequeue from with null. Failure to * do so can result in a loss of points. * * See the homework pdf for more information on implementation details. * * @see QueueInterface#dequeue() */

/**  * Dequeue from the front of the queue.  *  * This method should be implemented in O(1) time.  *  * @return the data from the front of the queue  * @throws java.util.NoSuchElementException if the queue is empty  */ 

@Override public T dequeue() {

}

/** * Add the given data to the queue. * * If sufficient space is not available in the backing array, you should * regrow it to double the current length. If a regrow is necessary, * you should copy elements to the front of the new array and reset * front to 0. * * @see QueueInterface#enqueue(T) */

/**  * Add the given data to the queue.  *  * This method should be implemented in (if array-backed, amortized) O(1)  * time.  *  * @param data the data to add  * @throws IllegalArgumentException if data is null  */ 

@Override public void enqueue(T data) {

}

@Override public T peek() {

}

@Override public boolean isEmpty() { // DO NOT MODIFY THIS METHOD! return size == 0; }

@Override public int size() { // DO NOT MODIFY THIS METHOD! return size; }

/** * Returns the backing array of this queue. * Normally, you would not do this, but we need it for grading your work. * * DO NOT USE THIS METHOD IN YOUR CODE. * * @return the backing array */ public Object[] getBackingArray() { // DO NOT MODIFY THIS METHOD! return backingArray; } }

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public interface QueueInterface { /**  * The initial capacity of a queue with fixed-size backing storage.  */  public static final int INITIAL_CAPACITY = 11; /**  * Dequeue from the front of the queue.  *  * This method should be implemented in O(1) time.  *  * @return the data from the front of the queue  * @throws java.util.NoSuchElementException if the queue is empty  */  T dequeue(); /**  * Add the given data to the queue.  *  * This method should be implemented in (if array-backed, amortized) O(1)  * time.  *  * @param data the data to add  * @throws IllegalArgumentException if data is null  */  void enqueue(T data); /**  * Retrieves the next data to be dequeued without removing it.  *  * This method should be implemented in O(1) time.  *  * @return the next data or null if the queue is empty  */  T peek(); /**  * Return true if this queue contains no elements, false otherwise.  *  * This method should be implemented in O(1) time.  *  * @return true if the queue is empty; false otherwise  */  boolean isEmpty(); /**  * Return the size of the queue.  *  * This method should be implemented in O(1) time.  *  * @return number of items in the queue  */  int size(); }