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Copy pathQueueArray.java
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79 lines (62 loc) · 1.54 KB
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package Queue;
public class QueueArray implements Queue{
private static final int CAP=7;//队列默认大小
private Object[] elements;
private int capacity;
private int front;
private int rear;
public QueueArray (int cap) {
this.capacity=cap+1;
this.elements=new Object[this.capacity];
this.front=0;
this.rear=0;
}
@Override
public int getSize() {
// TODO Auto-generated method stub
return (rear-front+capacity)%capacity;
}
@Override
public boolean isEmpty() {
// TODO Auto-generated method stub
return front==rear;
}
@Override
public void enqueue(Object e) {
// TODO Auto-generated method stub
if(getSize()==capacity-1) expandSpace();
elements[rear]=e;
rear=(rear+1)%capacity;
}
private void expandSpace() {
// TODO Auto-generated method stub
Object[] a=new Object[elements.length*2];
int i=front;
int j=0;
while(i!=rear) {
a[j++]=elements[i];
i=(i+1)%capacity;
}
elements=a;
capacity=elements.length;
front=0;
rear=j;
}
@Override
public Object dequeue() throws QueueEmptyException {
// TODO Auto-generated method stub
if(isEmpty())
throw new QueueEmptyException("错误，空队列");
Object obj=elements[front];
elements[front]=null;
front=(front+1)%capacity;
return obj;
}
@Override
public Object peek() throws QueueEmptyException {
// TODO Auto-generated method stub
if(isEmpty())
throw new QueueEmptyException("错误，空队列");
return elements[front];
}
}