(1,2,3),(4,5,6),(7,8,9),(10,11,12),(13,14,15),(16,17,18),(19,20,21),(22,23,24),(25,26,27),(28,29,30)每次报3的倍数,他报一个你就报两个,他报两个你就报一个.关键是你开始时得先抢到3,以此报3,6,9...27,30....