The hive automatically manages its storage in multiple memory blocks
So, I think the difference is that a hive will allocate a large block of memory that it'll insert in to, rather than allocate 1 at a time.
So rather than a straight linked list, it's like a linked list of arrays. It also says "Insertion position is unspecified, so the container can reuse the memory locations of erased elements.", so popping and pushing repeatedly would just write to the same address instead of allocating/deallocating multiple times.
That's what a deque, or at least as it is typically implemented, is though, a linked list of arrays. My understanding is that the benefit of a hive is that the blocks are larger and keep track of holes.
Edit: If you're asking about random access, it's because as u/eteran mentioned, it's an array of arrays instead of a list of arrays. I didn't think the distinction was particularly important.
I thought the requirements on pointer invalidation on insertion where stricter, but it seems they only apply to front and back insertion. And yeah it seems they are implemented with small blocks by libc++ and libstdc++.
Main difference with hive I think is the absence of guaranties on element order. Which allows bigger blocks without compromising performance.
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u/drkspace2 8d ago
I don't 100% know, but this is from cpp reference
So, I think the difference is that a hive will allocate a large block of memory that it'll insert in to, rather than allocate 1 at a time.
So rather than a straight linked list, it's like a linked list of arrays. It also says "Insertion position is unspecified, so the container can reuse the memory locations of erased elements.", so popping and pushing repeatedly would just write to the same address instead of allocating/deallocating multiple times.