🧩 Puzzle · Apply Hashing
Beat the scan
Numbers arrive one at a time. For each, say whether you've seen it before — by checking your buckets, not by rescanning the whole stream. That glance is what a hash set buys you.
4
7
4
2
7
9
2
5
your buckets (the set)
(empty)
First item incoming. Is it already in your buckets, or new?
Incoming: 4 —0/8