Using the below code for ping pong, create a "Game Tree".

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import java.awt.*;

import java.awt.event.*;

import java.awt.geom.Ellipse2D;

import java.awt.geom.Rectangle2D;

import java.util.HashMap;

import java.util.HashSet;

import javax.swing.*;

public class Game extends JPanel implements KeyListener, ActionListener {

private int height, width;

private Timer t = new Timer(5, this);

private boolean first;

private HashSet keys = new HashSet();

// Setting up the initial state

// pad

private final int SPEED = 1; // set the spped of the computer pad to 1

private int padH = 10, padW = 40; // set padding width and height to 10 and 40, respectively.

private int bottomPadX, topPadX;

private int inset = 10;

// ball

// Setting the ball size to 20, ball velocity to 1 along X and Y axis.

private double ballX, ballY, velX = 1, velY = 1, ballSize = 20;

// score

private int scoreTop, scoreBottom;

public Game() {

addKeyListener(this);

setFocusable(true);

setFocusTraversalKeysEnabled(false);

first = true;

t.setInitialDelay(100);

t.start();

}

@Override

protected void paintComponent(Graphics g) {

super.paintComponent(g);

Graphics2D g2d = (Graphics2D) g;

height = getHeight();

width = getWidth();

// initial positioning

if (first) {

bottomPadX = width / 2 - padW / 2;

topPadX = bottomPadX;

ballX = width / 2 - ballSize / 2;

ballY = height / 2 - ballSize / 2;

first = false;

}

// bottom pad

Rectangle2D bottomPad = new Rectangle(bottomPadX, height - padH - inset, padW, padH);

g2d.fill(bottomPad);

// top pad

Rectangle2D topPad = new Rectangle(topPadX, inset, padW, padH);

g2d.fill(topPad);

// ball

Ellipse2D ball = new Ellipse2D.Double(ballX, ballY, ballSize, ballSize);

g2d.fill(ball);

// scores

// Utility gives the payoff with numeric values for each player

// Updating the score of the Top and the Bottom player

String scoreB = "Bottom: " + new Integer(scoreBottom).toString();

String scoreT = "Top: " + new Integer(scoreTop).toString();

g2d.drawString(scoreB, 10, height / 2);

g2d.drawString(scoreT, width - 50, height / 2);

}

@Override

public void actionPerformed(ActionEvent e) {

// Results determines the outcome of a move

// side walls

if (ballX width - ballSize) {

velX = -velX;

}

// top / down walls

if (ballY

velY = -velY;

++ scoreBottom;

}

if (ballY + ballSize > height) {

velY = -velY;

++ scoreTop;

}

// bottom pad

if (ballY + ballSize >= height - padH - inset && velY > 0)

if (ballX + ballSize >= bottomPadX && ballX

velY = -velY;

// top pad

if (ballY

if (ballX + ballSize >= topPadX && ballX

velY = -velY;

ballX += velX;

ballY += velY;

// pressed keys

if (keys.size() == 1) {

if (keys.contains("LEFT")) {

bottomPadX -= (bottomPadX > 0) ? SPEED : 0;

}

else if (keys.contains("RIGHT")) {

bottomPadX += (bottomPadX

}

}

// AI

double delta = ballX - topPadX;

if (delta > 0) {

topPadX += (topPadX

}

else if (delta

topPadX -= (topPadX > 0) ? SPEED : 0;

}

repaint();

}

@Override

public void keyTyped(KeyEvent e) {}

@Override

public void keyPressed(KeyEvent e) {

int code = e.getKeyCode();

// Actions returns the set of legal moves in a state

switch (code) {

case KeyEvent.VK_LEFT:

keys.add("LEFT");

break;

case KeyEvent.VK_RIGHT:

keys.add("RIGHT");

break;

}

}

@Override

public void keyReleased(KeyEvent e) {

int code = e.getKeyCode();

// Actions returns the set of legal moves in a state

switch (code) {

case KeyEvent.VK_LEFT:

keys.remove("LEFT");

break;

case KeyEvent.VK_RIGHT:

keys.remove("RIGHT");

break;

}

}

public static void main(String[] args) {

JFrame frm = new JFrame();

frm.setTitle("Pong");

Game g = new Game();

frm.setContentPane(g);

frm.setSize(300, 700);

frm.setResizable(false);

frm.setVisible(true);

frm.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

}

}

Pong Bottom: 0 Top: 0 Pong Bottom: 0 Top: 0