2017-2018-1 20162307 队列加分项

2017-2018-1 20162307 队列加分项

要求

解题步骤

public class CircularArrayQueue<T> implements Queue<T>
{
private final int DEFAULT_CAPACITY = 100;
private int front, rear, count;
private T[] queue;
private T element;

public CircularArrayQueue()
{
front = rear = count = 0;
queue = (T[]) (new Object[DEFAULT_CAPACITY]);
}

public CircularArrayQueue (int initialCapacity)
{
front = rear = count = 0;
queue = ( (T[])(new Object[initialCapacity]) );
}

public void enqueue (T element)
{
if (size() == queue.length)
expandCapacity();

queue[rear] = element;
rear = (rear+1) % queue.length;

count++;
}

public T dequeue() throws EmptyCollectionException
{
if (isEmpty())
throw new EmptyCollectionException ("queue");

T result = queue[front];
queue[front] = null;
front = (front+1) % queue.length;

count--;

return result;
}

public T getElement()
{
return element;
}

public boolean isEmpty()
{
return (count == 0);
}

public int size()
{
return count;
}

public String toString()
{
String result = "";
int scan = 0;

while(scan < count)
{
if(queue[scan]!=null)
{
result += queue[scan].toString()+"\n";
}
scan++;
}

return result;
}

public void expandCapacity()
{
T[] larger = (T[])(new Object[queue.length *2]);

for(int scan=0; scan < count; scan++)
{
front=(front+1) % queue.length;
}

front = 0;
rear = count;
queue = larger;
}

public T[] first() {
return queue.clone ();
}
}