Efficient way of iterating over true bits in std::bitset?

Question

Is there a way of iterating over a (possibly huge) std::bitset that is linear in the number of bits that are set to true? I want to prevent ha

Answer 1

There are only two options that do much better than O(N) on total bits:

1. Using specialty bit-scan instructions available in certain architectures like BSF in x86.
2. There are O(log2(N)) algorithms for finding the lowest bit set in a word. This, of course does not scale well when the bitset is dense, rather than sparse. Resurrecting some foggy memory of mine, I found the source in the FXT library Details can be found in the FXT book (pdf), in section 1.3.2.