Snake

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.util.Random;

class MyPanel extends JPanel {

    private int mapHeight, mapWidth, x[], y[], length, headX, headY, coinX, coinY;
    private boolean used[][];
    private int direction;
    static public final int dirLeft = 1, dirRight = 2, dirUp = 3, dirDown = 4;
    private Random rand;
    private MyFrame frame;
    private Game game;

    public void pauseGame() {
        if (game != null) game.ok = false;
    }

    public void resumeGame() {
        game = new Game(this);
    }

    public void lose() {
        for (int i = 0; i < mapHeight; ++i)
            for (int j = 0; j < mapWidth; ++j) used[i][j] = false;
        headX = mapHeight / 2;
        headY = mapWidth / 2;
        x[0] = headX;
        y[0] = headY;
        on(headX, headY);
        length = 1;
        direction = 0;
        repaint();
    }

    private void on(int x,int y) {
        used[x][y] = true;
    }

    private void off(int x,int y) {
        used[x][y] = false;
    }

    private void nextCoin() {
        int x, y;
        do {
            x = rand.nextInt(mapHeight);
            y = rand.nextInt(mapWidth);
            if (!used[x][y]) break;
        } while (true);
        coinX = x;
        coinY = y;
    }

    public MyPanel(int x, int y, MyFrame frame) {
        this.frame = frame;
        rand = new Random();
        rand.setSeed(100);
        length = 0;
        mapHeight = x;
        mapWidth = y;
        setSize(20 * y, 20 * x);
        this.x = new int [x * y];
        this.y = new int [x * y];
        used = new boolean[x][];
        for (int i = 0; i < x; ++i) used[i] = new boolean[y];
        headX = x / 2;
        headY = y / 2;
        this.x[0] = headX;
        this.y[0] = headY;
        on(headX, headY);
        length = 1;
    }

    public void paint(Graphics g) {
        g.setColor(Color.white);
        g.fillRect(0, 0, 20 * mapWidth, 20 * mapHeight);
        for (int i = 0; i < mapHeight; ++i)
            for (int j = 0; j < mapWidth; ++j) {
                if (used[i][j]) g.setColor(Color.black);
                else g.setColor(Color.lightGray);
                g.fillRect(20 * j, 20 * i, 19, 19);
            }
        g.setColor(Color.blue);
        g.fillRect(20 * headY, 20 * headX, 19, 19);
        g.setColor(Color.red);
        g.fillRect(20 * coinY, 20 * coinX, 19, 19);
        frame.setTitle(length + "");
    }


    public int getDirectoin() {
        return direction;
    }

    public void setDirection(int newDir) {
        int cx = headX, cy = headY;
        switch (newDir) {
        case dirLeft:
            --cy;
            break;
        case dirRight:
            ++cy;
            break;
        case dirUp:
            --cx;
            break;
        case dirDown:
            ++cx;
            break;
        }
        if (length > 1 && cx == x[length - 2] && cy == y[length - 2]) return;
        direction = newDir;
        go();
    }

    public void go() {
        int n = length - 1;
        switch (direction) {
        case dirLeft:
            --headY;
            break;
        case dirRight:
            ++headY;
            break;
        case dirUp:
            --headX;
            break;
        case dirDown:
            ++headX;
            break;
        }
        if (headX < 0 || headX >= mapHeight || headY < 0 || headY >= mapWidth || used[headX][headY]) {
            lose();
            return;
        }
        if (headX != coinX || headY != coinY) {
            off(x[0], y[0]);
            for (int i = 0; i < n; ++i) {
                x[i] = x[i + 1];
                y[i] = y[i + 1];
            }
            x[n] = headX;
            y[n] = headY;
            on(headX, headY);
        } else {
            x[length] = headX;
            y[length] = headY;
            ++length;
            on(headX, headY);
            nextCoin();
        }
        if (game != null) game.ok = false;
        game = new Game(this);
        repaint();
    }

}

class Game implements Runnable {

    private MyPanel panel;
    private Thread t;
    public boolean ok;
    private int time;

    public Game(MyPanel panel) {
        this.panel = panel;
        t = new Thread(this);
        ok = true;
        time = 300;
        t.start();
    }

    public void run() {
        for (;;) {
            try {
                Thread.sleep(time);
                if (ok) panel.go();
            }
            catch (Exception e) {}
        }
    }
}

class MyKeyAdapter extends KeyAdapter {

    private MyPanel panel;

    public MyKeyAdapter (MyPanel panel) {
        this.panel = panel;
    }

    public void keyPressed(KeyEvent ke) {
        int code = ke.getKeyCode();
        if (code == KeyEvent.VK_DOWN) panel.setDirection(MyPanel.dirDown);
        if (code == KeyEvent.VK_UP) panel.setDirection(MyPanel.dirUp);
        if (code == KeyEvent.VK_LEFT) panel.setDirection(MyPanel.dirLeft);
        if (code == KeyEvent.VK_RIGHT) panel.setDirection(MyPanel.dirRight);
        if (code == KeyEvent.VK_ESCAPE) System.exit(0);
    }

}

class MyMenuHandler implements ActionListener {

    private MyPanel panel;

    public MyMenuHandler (MyPanel panel) {
        this.panel = panel;
    }

    public void actionPerformed(ActionEvent ae) {
        String msg = ae.getActionCommand();
        if (msg.equals("Новая игра")) panel.lose();
        if (msg.equals("Выход")) System.exit(0);
    }

}

class MyFrame extends JFrame {

    private MyPanel panel;
    private JMenuBar menuBar;
    private JMenu file;
    private JMenuItem newGame, exit;

    public MyFrame() {

        addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent we) {
                System.exit(0);
            }
        });

        setLayout(null);
        setResizable(false);

        newGame = new JMenuItem("Новая игра");
        exit = new JMenuItem("Выход");
        file = new JMenu("Файл");
        file.add(newGame);
        file.add(exit);
        menuBar = new JMenuBar();
        menuBar.add(file);
        setJMenuBar(menuBar);

        panel = new MyPanel(9, 19, this);
        add(panel);
        setSize(panel.getWidth() + 6, panel.getHeight() + 51);
        MyMenuHandler menuHandler = new MyMenuHandler(panel);
        addKeyListener(new MyKeyAdapter(panel));
        exit.addActionListener(menuHandler);
        newGame.addActionListener(menuHandler);
        setVisible(true);
    }

}

public class snake {

    public static void main(String[] args) {
        new MyFrame();
    }

}