2017-2018-1 20162307 队列加分项

2017-2018-1 20162307 队列加分项

要求

1 用实现循环队列
2 参考PPT用循环队列打印杨辉三角
3 用JDB或IDEA单步跟踪排队情况，画出队列变化图，包含自己的学号信息
4 把代码推送到代码托管平台
5 把完成过程写一篇博客：重点是单步跟踪过程和遇到的问题及解决过程
6 提交博客链接

解题步骤

• 1.查看PPT

1.想象队列为一个环形，让【0】在【N-1】之后
2.分析杨辉三角N行元素与N-1之间关系

• 2.参考15.6 CircularArrayQueue

  public class CircularArrayQueue implements Queue
  {
  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 ();
  }
  }

• 4. 杨辉三角(Pascal)