双色球--最多2个号码相同的内幕

虽然是标题党，但是功能却是能让双色球最多只有2个球号码相同，不知道没中过双色球或者只有2个双色球的小伙伴是不是买了假的双色球了啊。

代码如下：
class Doubleball{
public static void main(String[] args){
			String pool[]={"01","02","03","04","05","06"
		 ,"07","08","09","10","11","12","13","14",
	  	"15","16","17","18","19","20","21","22",
	  	"23","24","25","26","27","28","29","30",
	  	"31","32","33"};
				Random rad=new Random();
				String str=new String[6];
				int index=0;
				int i=0
				boolean used[]=new boolean[pool.length];
				while (index<str.length){
									i=rad.nextInt(pool.length);
									if(used[i]){
													continue;
									}
									index++;
									str[index]=pool[i];
									used[i]=ture;
				}
				Arrays.Sort(str);
				str=Arrays.copyOf(str,str.length+1);
				str[str.length-1]=pool[rad.nextInt(15)];
				System.out.println(Arrays.toString(str));
}
}

used数组已经将前6个中相同的跳过了，因此最多只能出现一个号码相同最终。