You are given a billion numbers but some are missing
This is interesting algorithm question. With my first attempt I have tried it with o(n**2) which needs improvement of course.
The question in detail
You are given a randomly listed billion numbers, from 1 to billion that is. And there are a couple of numbers missing from this list.
The task is to find those missing numbers from a billion list, and you are given a very limited memory resource – you can assume storage is not an issue.