In that case, you might still want to use a similar trick as a first pass (like a bloom filter), and go over the window that is potentially unique again with th

In that case, you might still want to use a similar trick as a first pass (like a bloom filter), and go over the window that is potentially unique again with the HashSet. This should still be faster than using the HashSet for all windows. https://en.wikipedia.org/wiki/Bloom_filter https://en.wikipedia.org/wiki/Bloom_filter