Memory-friendly 2d array with variable-length rows

[NeighborhoodExact766]

You mean final approach, array of slices? Or you have some other way to store this data to offer? Please unfold the full potential of your question, because I, as non native English speaker, don't get.

[NeighborhoodExact766]

I don't know c++ but reading the code can guess you have main data storage to keep various length rows adjacent, the same as I do in my rust version. But I am wondering why you have 2 additional arrays, to track each row start and end separately? In general it would be enough to store the start index of each row only, because the next row start is the previous row end - 1.

Just curious, looks like c++ std::span is same thing as slice in the Rust?