import java.awt.Color;
import java.awt.Graphics;

import javax.swing.JPanel;
import javax.swing.border.Border;
import javax.swing.border.EtchedBorder;


public class Board extends JPanel
{
	private int[] queenList=new int[8];
	public Board()
	{
		queens(queenList,2);
		this.setBorder(new EtchedBorder(EtchedBorder.RAISED,Color.WHITE,new Color(148,145,140)));
	}
	public static boolean safeLocation(int row,int col,int[]queenList)
	{
		int qRow,qCol;
		for(qCol=0;qCol<col;qCol++)
		{
			qRow=queenList[qCol];
			if(qRow==row)
				return false;
			else if(qCol==col)
				return false;
			else if(qCol-qRow==col-row||qCol+qRow==col+row)
			{
				return false;
			}
		}
		return true;
	}
	public static boolean queens(int[]queenList,int row)
	{
		queenList[0]=row;
		if(placeQueens(queenList,1))
		{
			return true;
		}
		else
			return false;
	}
	public static boolean placeQueens(int[]queenList,int col)
	{
		int row=0;
		boolean foundLocation;
		if(col==8)
			foundLocation=true;
		else
		{
			foundLocation=false;
			row=0;
		}
		while(row<8&&!foundLocation)
		{
			if(safeLocation(row,col,queenList))
			{   queenList[col]=row;
				foundLocation=placeQueens(queenList,col+1);
				if(!foundLocation)
					row++;
			}
			else
				row++;
		}
		return foundLocation;
	}
	public void paintComponent(Graphics g)
	{
		boolean white=true;
		
		super.paintComponent(g);
		g.setColor(Color.BLACK);
		for(int i=0;i<8;i++)
		{
			if(i%2==0)
			{
				white=false;
			}
			else
			{
				white=true;
			}
			for(int j=0;j<8;j++)
			{
				if(queenList[j]==i)
				{
					g.setColor(Color.ORANGE);
					if(white)
					{
						white=false;
					}
					else
					{
						white=true;
					}
				}
				else if(white)
				{
					g.setColor(Color.WHITE);
					white=false;
				}
				else
				{
					g.setColor(Color.BLACK);
					white=true;
				}
				
				g.fill3DRect(j*50, i*50,50,50,true);
			}
		}
	}
	
}

import java.awt.BorderLayout;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.Toolkit;

import javax.swing.JFrame;


public class GUI extends JFrame 
{
	Board gameboard;
	public GUI()
	{
		setTitle("八皇后");
		setSize(410,440);
		this.setResizable(false);
		Dimension scrSize=Toolkit.getDefaultToolkit().getScreenSize();
		Container container=getContentPane();
		setLayout(new BorderLayout());
		setLocation((scrSize.width-getSize().width)/2,(scrSize.height-getSize().height)/2);
		gameboard=new Board();
		add(gameboard,BorderLayout.CENTER);
	}
	public static void main(String[]args)
	{
		new GUI().setVisible(true);
	}
	
}