For this problem, in which the known solution-space is constrained to what can fit into a reasonably sized hash
and in which the total number of records and data-streams also fits into memory... a memory-based solution works just fine,
Ignoring the silly bit about "records and data-streams" fitting in memory. Exactly!
My mother had a brilliant solution to the problem of grease stains on carpets that involved brown paper and an iron; but you don't see me trotting out here at random.
there is utterly no reason to trundle out n-digit numbers to “prove” your point.
Beg to differ. There was a reason.
Your continued insistence to trot out the description of something that might prove to be a suitable to solution to some other problem at some other place and time gave me that reason.
I was really, really hoping that in this case you wouldn’t rush out once again to prove how smart you are. Let alone, as so many times before, publicly and at my expense.
The only smarts involved, is your exhibited lack thereof in posting inappropriate solutions to questions.
The only expense involved, is the time wasted by recipients of your "wisdoms", as they chase down blind alleys following them.
We found something we can agree on.