摘要： 判断x是否为2的若干次幂关键运算 i & （i - 1）i 和 i-1的二进制区别，i若为2的若干次幂，则i与i-1的区别为相反----------------10000000000000001000000000000000000000000000000001----------------20000000000000010000000000000000100000000000000001----------------40000000000000100000000000000001100000000000000001----------------800000000000010000 阅读全文