If you're using OR (unlike the OP) how are you removing the left side of the window? And still, even if the newest character is unique, previous characters might not be

Input: "abccdef"

Your algorithm will report a match at "bccd" since the "a" wasn't removed from the bitmask.

Yes, you are correct you would have to xor them back out

I swear I have seen this conversation before. A glitch?

If you XOR them together, you get back to the original conversation.

No - he responded on both parts of the thread where i commented. I started to respond here as well, then updated it to redirect to the other comment so we don't end up with two long threads.