360笔试

    public static void EX(int[] gailu,int money,List list,int time,int jiabantime)
	{
    if(time > gailu.length)
        {
            list.add(money);
            
        }
    else
        {
            if(gailu[time-1] == 0)
            {
                EX(gailu,money,list,time++,0);
            }
            else if(gailu[time-1] == 1)
            {
                jiabantime++;
                EX(gailu,money+jiabantime,list,time+1,jiabantime);
            }
            else if(gailu[time-1] == 2)
            {
            	EX(gailu,money,list,time+1,0);    
            	jiabantime++;
            	EX(gailu,money+jiabantime,list,time+1,jiabantime);
            }
        }
	}
    public static void main(String[] args)
    {
        Scanner sc = new Scanner(System.in);
        while(sc.hasNext())
        {
            int num = sc.nextInt();
            int[] gailu = new int[num];
            for(int i=0; i<num; i++)
                {
                    gailu[i] = sc.nextInt();
                }
            List<Integer> list = new ArrayList<Integer>();
            EX(gailu,0,list,1,0);
            long ans = 0;
            for(int i=0; i<list.size(); i++)
            {
                ans = ans + list.get(i);
            }
            System.out.println(ans/list.size());
        }

    }