I want to hide multiple elements in a valarray<int> which has consecutive integers starting from 0. For example, from {0, 1, 2, 3, 4, 5} to {0, 2, 3, 5}. I have found that I can use indirect array to specify elements indices with valarray<size_t>. However, I don't know how to generate valarray<size_t> with indices I want in O(1) complexity. O(1) complexity or at most O(logn) complexity is very important to me. So, I think gslice may be able to solve the problem, but I still can't figure out how to implement it.
Note: I use c++11