How to convert numpy arrays to vector<int>& (reference) with SWIG
I agree with @pschill: it’s not possible to get an std::vector without copying data.
One alternative is to use the std::span class template (introduced in C++20), or a similar span class template defined in a library.
Creating a std::span<int> would provide a view of existing data in a numpy array, and provide many convenient member functions (such as operator[], iterators, front(), back(), etc.) in C++.
Creating a span would never copy data from the numpy array.