假设先放3号小球,其放法有4,5,6,7,8号盒子共5种,
再放2号小球,其放法有3,4,5,6,7,8号盒子减去3号小球占用的盒子,共5种,
最后放1号小球,其放法有2,3,4,5,6,7,8号盒子减去2,3号小球占用的2个盒子,共5种,
故总放法为:5*5*5=125种.
假设先放3号小球,其放法有4,5,6,7,8号盒子共5种,
再放2号小球,其放法有3,4,5,6,7,8号盒子减去3号小球占用的盒子,共5种,
最后放1号小球,其放法有2,3,4,5,6,7,8号盒子减去2,3号小球占用的2个盒子,共5种,
故总放法为:5*5*5=125种.