队列加分项：杨辉三角-白红宇

队列加分项：杨辉三角

阅读量：5328 次

发布时间：2019-06-14

本文共 3071 字，大约阅读时间需要 10 分钟。

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

分析过程：

杨辉三角的构造，其两腰上的数都唯一，其余每个数都为其上方左右两数之和

为计算方便首尾加0

具体思路和老师的PPT大概一致（附图）

代码一：CircularArrayQueue

public class CircularArrayQueue
    
      implements Queue
     
      {    private final int DEFAULT_CAPACITY = 10000;    private int front, rear, size;    private T[] queue;    //-----------------------------------------------------------------// Creates an empty queue using the default capacity.//-----------------------------------------------------------------    public CircularArrayQueue()    {        front = rear = size = 0;        queue = (T[]) (new Object[DEFAULT_CAPACITY]);    }    //-----------------------------------------------------------------// Adds the specified element to the rear of this queue, expanding// the capacity of the queue array if necessary.//-----------------------------------------------------------------    public void enqueue (T element)    {        if (size == queue.length)            expandCapacity();        queue[rear] = element;        rear = (rear+1) % queue.length;        size++;    }    public void expandCapacity()    {        T[] larger = (T[])(new Object[queue.length*2]);        for (int index = 0; index < size; index++)            larger[index] = queue[(front+index) % queue.length];        front = 0;        rear = size;        queue = larger;    }    @Override    public T dequeue()    {        if (size == 0)            throw new EmptyCollectionException("queue");        T d = queue[front];        queue[front] = null;        front = (front+1)%queue.length;        size--;        return d;    }    @Override    public T first() {        return queue[front];    }    @Override    public boolean isEmpty() {        boolean course = false;        if(size ==0){            course = true;        }        return course;    }    @Override    public int size() {        return size;    }    @Override    public String toString(){        String result = "";        int scan = 0;        while(scan < size)        {            if(queue[scan]!=null)            {                result += queue[scan].toString()+"\n";            }            scan++;        }        return result;    }}

代码二：杨辉三角

import java.util.Scanner;public class YangHuiSanJiao {    public static void main(String[] args) {        System.out.println("输入行数：");        Scanner sca = new Scanner(System.in);        CircularArrayQueue qu = new CircularArrayQueue();        qu.enqueue(0);        qu.enqueue(1);        int b = sca.nextInt();        int z=0,j= 0,d;        System.out.println(1);        for (int a = 1;a<= b - 1; a++){            qu.enqueue(0);            for (int ai =1;ai< qu.size();ai++){                z= (int) qu.first();                qu.dequeue();                j = (int) qu.first();                d = z+j;                qu.enqueue(d);                System.out.print(d + " ");            }            System.out.println();        }    }}