import java.awt.*;
   import java.applet.*;
   import java.awt.event.*;

    public class SudokuBoard extends Applet
   {
      private Panel options;
      private Button easy,medium,hard,help,solve;
      private Panel sudokuGrid;
      private TextField[][] grid;
      private String[][] gridEasy,gridMedium,gridHard;
      private int board;
   
       public SudokuBoard()
      {
         options=new Panel();
         easy=new Button("Easy");
         medium=new Button("Medium");
         hard=new Button("Hard");
         help=new Button("Help");
         solve=new Button("Solve");
         help.setEnabled(false);
         solve.setEnabled(false);
         easy.addActionListener(new EasyButtonListener());
         medium.addActionListener(new MediumButtonListener());
         hard.addActionListener(new HardButtonListener());
         help.addActionListener(new HelpButtonListener());
         solve.addActionListener(new SolveButtonListener());
         options.add(easy);
         options.add(medium);
         options.add(hard);
         options.add(help);
         options.add(solve);
      
         sudokuGrid=new Panel();
         sudokuGrid.setLayout(new GridLayout(9,9));
         grid=new TextField[9][9];
         for(int i=0;i<9;i++)
         {
            for(int j=0;j<9;j++) 
            {
               grid[i][j]=new TextField(1);
               sudokuGrid.add(grid[i][j]);
            }
         }
      
         add(options,BorderLayout.NORTH);
         add(sudokuGrid,BorderLayout.CENTER);
      }
   
       public class EasyButtonListener implements ActionListener
      {
          public void actionPerformed(ActionEvent event)
         {
            grid[0][0].setText("1");
            grid[0][2].setText("3");
            grid[0][3].setText("5");
            grid[0][5].setText("8");
            grid[0][8].setText("9");
            grid[1][2].setText("8");
            grid[1][4].setText("4");
            grid[1][5].setText("7");
            grid[1][6].setText("6");
            grid[2][1].setText("4");
            grid[2][2].setText("7");
            grid[3][0].setText("2");
            grid[3][1].setText("7");
            grid[3][5].setText("3");
            grid[3][6].setText("4");
            grid[3][7].setText("9");
            grid[4][3].setText("9");
            grid[4][5].setText("2");
            grid[5][1].setText("5");
            grid[5][2].setText("9");
            grid[5][3].setText("6");
            grid[5][7].setText("2");
            grid[5][8].setText("1");
            grid[6][6].setText("2");
            grid[6][7].setText("7");
            grid[7][2].setText("2");
            grid[7][3].setText("4");
            grid[7][4].setText("9");
            grid[7][6].setText("8");
            grid[8][0].setText("3");
            grid[8][3].setText("7");
            grid[8][5].setText("1");
            grid[8][6].setText("9");
            grid[8][8].setText("4");
         
            gridEasy[0][0]="1";
            gridEasy[0][1]="9";
            gridEasy[0][2]="3";
            gridEasy[0][3]="5";
            gridEasy[0][4]="6";
            gridEasy[0][5]="8";
            gridEasy[0][6]="7";
            gridEasy[0][7]="4";
            gridEasy[0][8]="2";
            gridEasy[1][0]="5";
            gridEasy[1][1]="2";
            gridEasy[1][2]="8";
            gridEasy[1][3]="1";
            gridEasy[1][4]="4";
            gridEasy[1][5]="7";
            gridEasy[1][6]="6";
            gridEasy[1][7]="3";
            gridEasy[1][8]="9";
            gridEasy[2][0]="6";
            gridEasy[2][1]="4";
            gridEasy[2][2]="7";
            gridEasy[2][3]="2";
            gridEasy[2][4]="3";
            gridEasy[2][5]="9";
            gridEasy[2][6]="1";
            gridEasy[2][7]="5";
            gridEasy[2][8]="8";
            gridEasy[3][0]="2";
            gridEasy[3][1]="7";
            gridEasy[3][2]="1";
            gridEasy[3][3]="8";
            gridEasy[3][4]="5";
            gridEasy[3][5]="3";
            gridEasy[3][6]="4";
            gridEasy[3][7]="9";
            gridEasy[3][8]="6";
            gridEasy[4][0]="4";
            gridEasy[4][1]="3";
            gridEasy[4][2]="6";
            gridEasy[4][3]="9";
            gridEasy[4][4]="1";
            gridEasy[4][5]="2";
            gridEasy[4][6]="5";
            gridEasy[4][7]="8";
            gridEasy[4][8]="7";
            gridEasy[5][0]="8";
            gridEasy[5][1]="5";
            gridEasy[5][2]="9";
            gridEasy[5][3]="6";
            gridEasy[5][4]="7";
            gridEasy[5][5]="4";
            gridEasy[5][6]="3";
            gridEasy[5][7]="2";
            gridEasy[5][8]="1";
            gridEasy[6][0]="9";
            gridEasy[6][1]="1";
            gridEasy[6][2]="4";
            gridEasy[6][3]="3";
            gridEasy[6][4]="8";
            gridEasy[6][5]="6";
            gridEasy[6][6]="2";
            gridEasy[6][7]="7";
            gridEasy[6][8]="5";
            gridEasy[7][0]="7";
            gridEasy[7][1]="6";
            gridEasy[7][2]="2";
            gridEasy[7][3]="4";
            gridEasy[7][4]="9";
            gridEasy[7][5]="5";
            gridEasy[7][6]="8";
            gridEasy[7][7]="1";
            gridEasy[7][8]="3";
            gridEasy[8][0]="3";
            gridEasy[8][1]="8";
            gridEasy[8][2]="5";
            gridEasy[8][3]="7";
            gridEasy[8][4]="2";
            gridEasy[8][5]="1";
            gridEasy[8][6]="9";
            gridEasy[8][7]="6";
            gridEasy[8][8]="4";
         
            board=1;
            help.setEnabled(true);
            solve.setEnabled(true);
         }
      }
   
       public class MediumButtonListener implements ActionListener
      {
          public void actionPerformed(ActionEvent event)
         {
         
         
            board=2;
            help.setEnabled(true);
            solve.setEnabled(true);
         }
      }
   
       public class HardButtonListener implements ActionListener
      {
          public void actionPerformed(ActionEvent event)
         {
         
         
            board=3;
            help.setEnabled(true);
            solve.setEnabled(true);
         }
      }
   
       public class HelpButtonListener implements ActionListener
      {
         int run=1;
      
          public void actionPerformed(ActionEvent event)
         {
            if(board==1)
            {
               while(run!=0)
               {
                  for(int i=0;i<9;i++)
                  {
                     for(int j=0;j<9;j++)
                     {
                        if(grid[i][j].getText()!=gridEasy[i][j])
                        {
                           grid[i][j].setText(gridEasy[i][j]);
                           run=0;
                        }
                     }
                  }
               }
               run=1;
            }
         
            if(board==2)
            {
               while(run!=0)
               {
                  for(int i=0;i<9;i++)
                  {
                     for(int j=0;j<9;j++)
                     {
                        if(grid[i][j].getText()!=gridMedium[i][j])
                        {
                           grid[i][j].setText(gridMedium[i][j]);
                           run=0;
                        }
                     }
                  }
               }
               run=1;
            }
         
            if(board==3)
            {
               while(run!=0)
               {
                  for(int i=0;i<9;i++)
                  {
                     for(int j=0;j<9;j++)
                     {
                        if(grid[i][j].getText()!=gridHard[i][j])
                        {
                           grid[i][j].setText(gridHard[i][j]);
                           run=0;
                        }
                     }
                  }
               }
               run=1;
            }
         }
      }
   
       public class SolveButtonListener implements ActionListener
      {
          public void actionPerformed(ActionEvent event)
         {
            if(board==1)
            {
               for(int i=0;i<9;i++)
               {
                  for(int j=0;j<9;j++)
                  {
                     if(grid[i][j].getText()!=gridEasy[i][j])
                     {
                        grid[i][j].setText(gridEasy[i][j]);
                     }
                  }
               }
            }
         
            if(board==2)
            {
               for(int i=0;i<9;i++)
               {
                  for(int j=0;j<9;j++)
                  {
                     if(grid[i][j].getText()!=gridMedium[i][j])
                     {
                        grid[i][j].setText(gridMedium[i][j]);
                     }
                  }
               }
            
               if(board==3)
               {
                  for(int i=0;i<9;i++)
                  {
                     for(int j=0;j<9;j++)
                     {
                        if(grid[i][j].getText()!=gridHard[i][j])
                        {
                           grid[i][j].setText(gridHard[i][j]);
                        }
                     }
                  }
               }
            }
         }
      }
   }