Data structure to build and lookup set of integer ranges

Question

I have a set of uint32 integers, there may be millions of items in the set. 50-70% of them are consecutive, but in input stream they appear in unpredictable ord

Answer 1

AFAIK there is no such algorithm that search over integer list in O(1).

One only can do O(1) search with vast amount of memory.

So it is not very promising to try to find O(1) search algorithm over list of range of integer.

On the other hand, you could try time/memory trade-off approach by carefully examining your data set (eventually building a kind of hash table).