import java.awt.*;import java.awt.event.*;import java.util.*;import java.applet.*;import javax.swing.*;public class TTTAI extends Applet implements MouseListener,ActionListener{	String[][] board,test;	HashMap badMoves=new HashMap();	HashMap goodMoves=new HashMap();	HashMap tieMoves=new HashMap();	Button nG,learn,rs,help;	boolean humanTurn;	Random r=new Random();	int lastX;	int lastY;	public void start()	{		setLayout(null);		addMouseListener(this);		nG=new Button("NEW GAME");		rs=new Button("CLEAR MEMORY");		learn=new Button("LEARN");		help=new Button("HELP");		nG.setBounds(10,1,80,20);		nG.addActionListener(this);		help.setBounds(10,328,280,20);		help.addActionListener(this);		rs.setBounds(100,1,105,20);		rs.addActionListener(this);		learn.setBounds(215,1,75,20);		learn.addActionListener(this);		add(nG);		add(rs);		add(help);		add(learn);	}	public void init()	{		humanTurn=true;		lastX=-1;lastY=-1;		board=new String[3][3];		for(int cv=0;cv<9;cv++)		{			board[cv/3][cv%3]=" ";		}	}	public void learn()	{		for(int cv=0;cv<100;cv++)		{			for(int cv2=0;cv2<50;cv2++)			{				int x;				int y;				boolean isValid=false;				while(!isValid)				{					x=r.nextInt(3);					y=r.nextInt(3);					lastX=x;					lastY=y;					isValid=move(x,y,"X");				}			}		}		init();		repaint();	}	public void paint(Graphics gr)	{		Graphics g=gr;		for(int cv=0;cv<4;cv++)		{			g.drawLine(0,100*cv+24,300,100*cv+24);			g.drawLine(100*cv,24,100*cv,324);		}		for(int cv=0;cv<3;cv++)		{			for(int cv2=0;cv2<3;cv2++)			{				g.drawString(board[cv][cv2],100*cv+50,100*cv2+75);			}		}		gr=g;	}	public void mouseEntered(MouseEvent e){}	public void mouseExited(MouseEvent e){}	public void mousePressed(MouseEvent e)	{		if(humanTurn)		{			if(e.getX()>299||e.getX()<0||e.getY()<25||e.getY()>323)			return;			int x=e.getX()/100;			int y=(e.getY()-24)/100;			lastX=x;			lastY=y;			move(x,y,"X");		}	}	public void mouseReleased(MouseEvent e){}	public void mouseClicked(MouseEvent e){}	public boolean move(int x,int y,String player)	{		if(board[x][y].equals(" "))		board[x][y]=player;		else return false;		humanTurn=false;		repaint();		String win=checkWIN(player);		if(win.equals("yes"))		{			showStatus(player+" wins!");			return true;		}		if(win.equals("tie"))		{			showStatus("DRAW");			return true;		}		if(player.equals("X"))		computerMove();		return true;	}	public void computerMove()	{		String tempBoard[][]=tempBoard();		int cv=0;		while(cv<9)		{			if(board[cv%3][cv/3].equals(" "))			{				tempBoard[cv%3][cv/3]="O";				int y=cv/3;				int x=cv%3;				if(!badMoves.containsKey(getString(tempBoard)))				{										move(x,y,"O");					humanTurn=true;					repaint();					return;				}			}			cv++;			tempBoard=tempBoard();		}		String[][] b=tempBoard();		b[lastX][lastY]=" ";		badMoves.put(getString(b),"bad");		cv=0;		int x=r.nextInt(3);		int y=r.nextInt(3);		boolean success=move(x,y,"O");		while(!success)		{			x=r.nextInt(3);			y=r.nextInt(3);			success=move(x,y,"O");		}		humanTurn=true;		repaint();	}	public String checkWIN(String p)	{		if((board[0][0].equals(board[0][1])&&board[0][0].equals(board[0][2])&&board[0][0].equals(p))||(board[1][0].equals(board[1][1])&&board[1][0].equals(board[1][2])&&board[1][0].equals(p))||(board[2][0].equals(board[2][1])&&board[2][0].equals(board[2][2])&&board[2][0].equals(p))||(board[0][0].equals(board[1][0])&&board[0][0].equals(board[2][0])&&board[0][0].equals(p))||(board[0][1].equals(board[1][1])&&board[0][1].equals(board[2][1])&&board[0][1].equals(p))||(board[0][2].equals(board[1][2])&&board[0][2].equals(board[2][2])&&board[0][2].equals(p))||(board[0][0].equals(board[1][1])&&board[0][0].equals(board[2][2])&&board[0][0].equals(p))||(board[0][2].equals(board[1][1])&&board[0][2].equals(board[2][0])&&board[2][0].equals(p)))		{			if(p.equals("X"))			{				test=board;				board[lastX][lastY]=" ";				badMoves.put(getString(board),"bad");			}			init();			repaint();			return "yes";		}		for(int cv=0;cv<9;cv++)		{			if(board[cv%3][cv/3].equals(" "))			return "no";		}		init();		repaint();		return "tie";	}	public String getString(String b[][])	{		return b[0][0]+b[0][1]+b[0][2]+b[1][0]+b[1][1]+b[1][2]+b[2][0]+b[2][1]+b[2][2];	}	public String[][] tempBoard()	{		String[][] tB=new String[3][3];		for(int cv=0;cv<9;cv++)		{			tB[cv/3][cv%3]=board[cv/3][cv%3];		}		return tB;	}	public void actionPerformed(ActionEvent e)	{		if(e.getSource()==rs)		{			badMoves=new HashMap();			goodMoves=new HashMap();			tieMoves=new HashMap();			init();			repaint();		}		if(e.getSource()==nG)		{			init();			repaint();		}		if(e.getSource()==learn)		{			learn();		}		if(e.getSource()==help)		{			JOptionPane.showMessageDialog(null,"You are X.\nThe computer is O.\n\nGet 3-in-a-row to win.\n\nClick NEW GAME to create a new game.\nClick LEARN to make the computer smarter.\n(If you click it 5 or more times then it will be VIRTUALLY undefeatable)\nClick CLEAR MEMORY to make the computer stupid again.","HELP",JOptionPane.INFORMATION_MESSAGE);		}	}}