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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);
}
}