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

public class Paskal extends Applet
{
  Button btn1,btn2;
  TextField tf,tf1,tf2;
  PaskalTr pas_tr=null;
  int[]aiTW=new int[253];
  int iTextHeight,iTextWidth,foo,foo1; 
  int result; 
  boolean bB1=false,bB2=false; // какая из кнопок была нажата.

  public String getAppletInfo()
	{
		return "Name: PaskalTr\r\n" +
		       "Author: Alex\r\n" +
		       "Created for get credit";
	}
/////////////////////////////////////////////////  
  public boolean action(Event evt,Object obj)
  {
    if(evt.target instanceof Button)
    {
      if(evt.target.equals(btn1))
      {
        foo= new Integer(tf.getText()).intValue();
        if(foo<2 || foo>20) foo=2;
        pas_tr=new PaskalTr(foo);
        repaint();
        bB1=true;
        bB2=false;
        return true;  
      }
      if(evt.target.equals(btn2))
      {
        result=PaskalTr.getCNK(new Integer(tf1.getText()).intValue(),
          new Integer(tf2.getText()).intValue());
        bB2=true;
        bB1=false;
        repaint();
        return true;  
      }
    }
    return false;
  }

  public void init()
  {
    btn1=new Button("Построить");
    btn2=new Button("Cочетания");
    tf=new TextField(2);
    tf1=new TextField(2);
    tf2=new TextField(2);
    add(btn1);    add(tf);
    add(btn2);    add(tf1);
    add(tf2);
    Graphics g=getGraphics();
    FontMetrics fm=g.getFontMetrics();
    iTextHeight=fm.getHeight();
    aiTW=fm.getWidths();
    iTextWidth=(aiTW[193]+aiTW[197]+aiTW[196]+aiTW[195])/4;
  }
  

//-----------------------------------------------------------
  public void paint(Graphics g)
  {
    if(bB1) pas_tr.show(g,iTextHeight,iTextWidth);
      else if(bB2)
    g.drawString(Integer.toString(result),10,40);

  }
}


/////////////////////////////////////////////////////
class PaskalTr 
{
	
	int t_pask[][],iTrRow;

  public void show(Graphics g,int iTextHeight,int iTextWidth)
	{
    int i,j=0;
    Rectangle rect;

    rect=g.getClipRect();
    g.clearRect(10,40,rect.width-10,rect.height-40);
    g.drawString("Треугольник Паскаля",10, 40);
    for ( i=0;i<iTrRow;i++){
      for ( j=0;j<i+1;j++){
        if(t_pask[i][j]>99) continue;
        g.drawString(Integer.toString(t_pask[i][j]),10+((iTextWidth+3)*2*j), 40+(iTextHeight)*(i+1));
      }
    }
  } 

 static public int getCNK(int n,int k)
 {
   PaskalTr pt=new PaskalTr(n);
   return pt.t_pask[n][k];
 }

 public PaskalTr(int b)
 {
    int i,j;
    iTrRow=b+1;
    
    t_pask=new int[iTrRow][];
    t_pask[0]=new int[1];
    t_pask[1]=new int[2];
    t_pask[0][0]=1;
    t_pask[1][0]=1;
    t_pask[1][1]=1;
    
    for (i=2;i<iTrRow;i++)
    {
      t_pask[i]=new int[i+1];
      for (j=0;j<i+1;j++)
      {
        if(j==0 || j==i) t_pask[i][j]=1;
        else
          t_pask[i][j]=(t_pask[i-1][j-1]+t_pask[i-1][j]);
      }
    }
 }
}