import java.util.ArrayList;
import java.util.Collections;
import java.util.Random;

public class Draw {
   private ArrayList<Integer>list;
   public Draw(){
       list = new ArrayList<Integer>();
   }
   public void deal(int num){
       //向容器中添加奖券(使用循环)
      for (int i=0;i<num;i++){
               list.add(i);
               
           }
       
       //打乱顺序
        Collections.shuffle(list);
      
        }
  public void drawLotter(int n){
      //产生N个指定范围(e-list.size())的随机数
      Random rd = new Random();

      for(int i=0;i<n;i++ ){
           int index = rd.nextInt(list.size());
      
      
      /*获得容器中以产生的随机数为下标的元素内容
       * 即为获奖的奖券的抽奖号,输出
       */
      System.out .print(list.get(index)+"\t");;
     //将已获奖的元素(奖券)从容器中删除 
      list.remove(index);
     }
   System.out.println();
  } 
   public static void main(String[] args){
    //TODO AUTO-generated method stub
     Draw dr = new Draw();
     dr.deal(2000);
     System.out.println("-----一等奖-----"); 
     dr.drawLotter(3);
     System.out.println("-----二等奖-----");
     dr.drawLotter(10);
     System.out.println("-----三等奖-----"); 
     dr.drawLotter(20);
 }
}