demo.java

学习数据结构的最好辅助工具,快速帮助你熟悉数据结构的相关技术

import java.awt.*;
public class Demo extends Canvas
{
	private int sleepTime = 40;
	static final int NullPointer = 99999;
	private int m_numNodes, m_num;
	private String m_data;
	private char m_pName[] = {'L','p'};
	private boolean m_hasNewNode = false, m_hasData = false, m_hasP = false, m_LP = false;
	private int m_newNodePlace = 50, m_nodePlace = 0;
	private boolean m_animating = false, m_headNull = false, m_nodeNull = false;
	
	public Demo(int n, String data)
	{
		m_numNodes = n;
		m_data = data;
		m_num = -1;
	}
	
	public void reset(int n, String data)
	{
		m_numNodes = n;
		m_data = data;
		repaint();
		m_num = -1;
		m_hasNewNode = false; m_hasData = false; m_hasP = false; m_LP = false;
		m_newNodePlace = 50; m_nodePlace = 0;
		m_animating = false;
		m_headNull = false;
		m_nodeNull = false;
	}
	
	public void create()
	{
		m_num = 0;
		repaint();
	}
	
	public void setHeadNull()
	{
		m_headNull = true;
		repaint();
	}
	
	public void newNode()
	{
		m_hasNewNode = true;
		m_hasData = false;
		m_hasP = false;
		repaint();
	}
	
	public void setData()
	{
		m_hasData = true;
		repaint();
	}
	
	public void setNextPointer()
	{
		if(m_num>=1) m_hasP = true;
		else m_nodeNull = true;
		repaint();
	}
	
	public void setPointer()
	{
		m_LP = false;
		m_headNull = false;
		m_hasP = false;
		m_animating = true;
		repaint();
	}
	
	public void paint(Graphics p1)
	{
		int baseline = 145;
		// draw head node
		int d = 300/(m_numNodes+1);
		p1.drawLine(d-35, baseline, d-15, baseline);
		p1.drawLine(d-15, baseline, d-20, baseline+5);
		p1.drawLine(d-15, baseline, d-20, baseline-5);
		p1.drawChars(m_pName, 0, 1, d-35, baseline-3);
		if( m_num>=0 )
		{
			p1.drawRect(d-15, baseline-10, 30, 20);
			p1.drawLine(d, baseline-10, d, baseline+10);
			if(m_LP)
			{
				p1.drawLine(d+5, baseline, 2*d-15, baseline);
				p1.drawLine(2*d-20, baseline+5, 2*d-15, baseline);
				p1.drawLine(2*d-20, baseline-5, 2*d-15, baseline);
			}
			else if(m_headNull)
			{
				p1.drawLine(d+2, baseline-5, d+12, baseline-5);
				p1.drawLine(d+12, baseline-5, d+7, baseline+5);
				p1.drawLine(d+2, baseline-5, d+7, baseline+5);
			}
			else if(m_animating)
			{
				p1.drawLine(d+5, baseline, d+20, baseline);
				p1.drawLine(d+20, baseline, d+20, baseline-m_newNodePlace);
				p1.drawLine(d+20, baseline-m_newNodePlace, 2*d-15, baseline-m_newNodePlace);
				p1.drawLine(2*d-20, baseline-m_newNodePlace-5, 2*d-15, baseline-m_newNodePlace);
				p1.drawLine(2*d-20, baseline-m_newNodePlace+5, 2*d-15, baseline-m_newNodePlace);
			}
			// draw new node
			if( m_hasNewNode )
			{
				p1.drawRect(2*d-15, baseline-10-m_newNodePlace, 30, 20);
				p1.drawLine(2*d, baseline-10-m_newNodePlace, 2*d, baseline+10-m_newNodePlace);
				p1.drawLine(2*d-5, baseline-10-m_newNodePlace, 2*d-5, baseline-80);
				p1.drawLine(2*d-5, baseline-10-m_newNodePlace, 2*d-5, baseline-15-m_newNodePlace);
				p1.drawLine(2*d-5, baseline-10-m_newNodePlace, 2*d, baseline-15-m_newNodePlace);
				p1.drawLine(2*d-5, baseline-10-m_newNodePlace, 2*d-10, baseline-15-m_newNodePlace);
				p1.drawChars(m_pName, 1, 1, 2*d-5, baseline-82);
				if( m_hasData )	p1.drawString(m_data.substring(m_num, m_num+1),
											  2*d-10, baseline+5-m_newNodePlace);
				if( m_hasP )
				{
					p1.drawLine(2*d+8, baseline-50, 2*d+8, baseline-25);
					p1.drawLine(2*d-5, baseline-25, 2*d+8, baseline-25);
					p1.drawLine(2*d-5, baseline-25, 2*d-5, baseline-10);
					p1.drawLine(2*d-5, baseline-10, 2*d-10, baseline-15);
					p1.drawLine(2*d-5, baseline-10, 2*d, baseline-15);
				}
				else if( m_nodeNull )
				{
					p1.drawLine(2*d+2, baseline-5-m_newNodePlace, 2*d+12, baseline-5-m_newNodePlace);
					p1.drawLine(2*d+12, baseline-5-m_newNodePlace, 2*d+7, baseline+5-m_newNodePlace);
					p1.drawLine(2*d+2, baseline-5-m_newNodePlace, 2*d+7, baseline+5-m_newNodePlace);
				}
			}
			// draw other nodes
			for(int i=1; i<=m_num; i++)
			{
				int x = (i+1)*d;
				p1.drawRect(x+m_nodePlace-15, baseline-10, 30, 20);
				p1.drawLine(x+m_nodePlace, baseline-10, x+m_nodePlace, baseline+10);
				p1.drawString(m_data.substring(m_num-i, m_num-i+1), x+m_nodePlace-10, baseline+6);
				if( i<m_num )
				{
					p1.drawLine(x+m_nodePlace+5, baseline, x+m_nodePlace+d-15, baseline);
					p1.drawLine(x+m_nodePlace+d-20, baseline+5, x+m_nodePlace+d-15, baseline);
					p1.drawLine(x+m_nodePlace+d-20, baseline-5, x+m_nodePlace+d-15, baseline);
				}
				else
				{
					p1.drawLine(x+m_nodePlace+2, baseline-5, x+m_nodePlace+12, baseline-5);
					p1.drawLine(x+m_nodePlace+12, baseline-5, x+m_nodePlace+7, baseline+5);
					p1.drawLine(x+m_nodePlace+2, baseline-5, x+m_nodePlace+7, baseline+5);
				}
			}
			if(m_animating)
			{
				m_nodePlace += 30/(m_numNodes+1);
				m_newNodePlace -= 5;
				if(m_newNodePlace<=0)
				{
					m_animating = false;
					m_num ++;
					m_newNodePlace = 50;
					m_nodePlace = 0;
					m_hasNewNode = false;
					m_LP = true;
					m_nodeNull = false;
				}
				try{ Thread.sleep(sleepTime); }
				catch(InterruptedException e){}
				repaint();
			}
		}
	}
}