Efficient way to get all matching bitmasks?

Lets say I have some patterns as 64 bits integers. Given a 64 integer n how to list all patterns matching n efficiently?

More precisely I am interested in this set: {p_i in patterns such as (n & p_i) == p_i}

Thanks for your help

https://stackoverflow.com/questions/65534055/efficient-way-to-get-all-matching-bitmasks January 02, 2021 at 05:59AM