漫游猫认证
用一个0两个2和3个6能组成不同的六位数的个数:
A(6,6)/(A(2,2)*A(3,3) - A(5,5)/(A(2,2)*A(3,3)
=720/(2*6)-120/(2*6)
=600/(2*6)
=50 个