package eight_queen;
import java.awt.AWTEvent;
import java.awt.AlphaComposite;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Composite;
import java.awt.EventQueue;
import java.awt.Frame;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowEvent;
import java.lang.reflect.InvocationTargetException;
import java.util.Random;
import java.util.Scanner;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
/**
*
* @author rooparam
*/
class Locations {
public Locations(int size ) {
at = new int[size];
top = 0; // next coloumn of a queen
}
public int top;
public int[] at;
}
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MyButton( ) {
super("continue");
}
}
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Board ( Locations Q ) {
queens = Q;
//setSize(640, 480);
setBackground(Color.WHITE);
}
@Override
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Image image = Toolkit.getDefaultToolkit().getImage("eight_queen/smvdu_logo_1.gif");
g.drawImage(image, 0, 0, getBounds().width, getBounds().height, this);
drawBoard ( g );
drawQueens(g);
drawRemaining(g);
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String str = "Coder : Rooparam Chaudhary";
g.drawString(str, getBounds().width - 180, getBounds().height - 10);
}
private Locations queens;
private void drawRemaining(Graphics g2) {
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float alpha = 0.8f;
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int width = getBounds( ).width;
int height = getBounds( ).height;
int w_Q = width / queens.at.length;
int h_Q = height / queens.at.length;
for(int col = queens.top; col < queens.at.length; ++col) {
for(int row = 0; row < queens.at.length; ++row) {
if( !Main.isSafe(queens, row, col) )
g.fill3DRect(col*w_Q, row*h_Q, w_Q, h_Q, true);
}
}
g.setComposite(oldC);
}
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int width = getBounds( ).width;
int height = getBounds( ).height;
int w_Q = width / queens.at.length;
int h_Q = height / queens.at.length;
for(int col = 0; col < queens.top; ++col) {
drawQueen(g, col*w_Q, queens.at[col]*h_Q, w_Q, h_Q);
}
}
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float alpha = 0.9f;
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int width = getBounds( ).width;
int height = getBounds( ).height;
int w_Q = width / queens.at.length;
int h_Q = height / queens.at.length;
for(int col = 0; col < queens.at.length; ++col) {
for(int row = 0; row < queens.at.length; ++row) {
//g.fillRect(col*w_Q, row*h_Q, w_Q, h_Q);
g.fill3DRect(col*w_Q, row*h_Q, w_Q, h_Q, true);
togglePen(g, Color.ORANGE );
}
togglePen(g, Color.ORANGE);
}
g.setComposite(oldC);
}
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if( g.getColor( ) == Color.WHITE )
g.setColor(clr);
else
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}
private void drawQueen(Graphics g, int x, int y, int width,
int height) {
Color oldPen = g.getColor( );
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g.fillArc ( x + width/8, y + 7*height/8, 3*width/4, height/4, 0, 180);
int lines = 16;
double xi = x + width/8.0;
double yi = y + height/2.0;
double step_x = 3.0*width/(4*lines);
double step_y = height/(2.0*lines);
g.drawLine((int)xi, (int)yi, (int)(xi+step_x), (int)( y+height-2) );
for(int i=0; i < lines/2; ++i) {
xi += step_x; yi -= step_y;
g.drawLine((int)xi, (int)yi, (int)xi, (int)(y+height-2.0));
}
for(int i=1; i < lines/2; ++i) {
xi += step_x; yi += step_y;
g.drawLine((int)xi, (int)yi, (int)xi, (int)(y+height-2.0));
}
xi += step_x; yi += step_y;
g.drawLine((int)xi, (int)yi, (int)(xi-step_x), (int)(y+height-2.0));
g.setColor(oldPen);
}
}
public class Main extends JFrame {
Main( Locations Q ) {
enableEvents(AWTEvent.WINDOW_EVENT_MASK);
setLocation(100, 100);
setSize(640, 480);
setTitle("Eight Queens Problem (DFS using Backtracing)");
Board canvas = new Board ( Q );
button = new MyButton( );
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Main.go(true);
Main.window.repaint( );
}
};
button.addActionListener(buttonclk);
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setVisible(true);
}
@Override
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}
/**
* @param args the command line arguments
*/
public static void main(String[] args) {
int size;
Scanner in = new Scanner(System.in);
System.out.println("Eight Queen Problem (DFS using Backtracing)");
//System.out.print("N : ");
//size = in.nextInt( );
//System.out.println("Wait .... ");
size = 8;
Locations queens = new Locations(size); // stores row of queens
Main.solution = queens;
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public void run() {
Main.window = new Main(Main.solution);
}
});
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do {
int initial = dice.nextInt(size);
queens.at[(queens.top)++] = initial;
} while ( solve (queens, window) == false );
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public void run() {
Main.button.setText("D O N E");
Main.button.removeActionListener(buttonclk);
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JOptionPane.showMessageDialog(null, "THANK YOU. source code at http://rooparam.blogspot.com", "rooparam", JOptionPane.INFORMATION_MESSAGE);
}
};
Main.button.addActionListener(buttonclk);
}
});
System.out.println("Positions of queens in Rows from left to right");
for ( int i=0; i< queens.at.length; ++i ) {
System.out.printf("%d ", queens.at[i]);
}
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}
private static boolean solve(Locations queens, Frame window
) {
if(queens.top >= queens.at.length)
return true;
Main.go(false);
while (!proceed) {
try {
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Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);
}
}
try {
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public void run() {
Main.window.repaint();
}
});
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Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);
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Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);
}
for(int i=0; i < queens.at.length; ++i) {
if ( isSafe ( queens, i, queens.top ) ) {
queens.at[queens.top++] = i;
if( solve ( queens, window) )
return true;
}
}
queens.top--;
return false;
}
static boolean isSafe(Locations queens, int check, int col) {
for( int i=0; i < queens.top; ++i ) {
int col_i = i;
int row_i = queens.at[i];
int col_test = col;
int row_test = check;
// checking whether in same coloumn of in same row
if ( col_i == col_test || row_i == row_test )
return false;
// digonal check
if ( ( col_i + row_i ) == ( col_test + row_test ) )
return false;
if ( ( col_i - row_i ) == ( col_test - row_test ) )
return false;
}
return true;
}
static boolean proceed = false;
static Frame window = null;
static Locations solution = null;
public static void go(boolean b){
myLock.lock( );
try {
proceed = b;
} finally
{
myLock.unlock( );
}
}
public static final Lock myLock = new ReentrantLock( );
static MyButton button;
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}
