Does visiting pages A and B on day 1 and visiting page A on day 2 also make the sentence true? I think that's the source of ambiguity (or maybe it's ambiguous to me only because English is not my native language).
The user has visited A and B on day 1, and A on day 2.
So the total page hits is (A, B, A). Remove duplicates and you have (A, B) which makes the sentence true.
The noun is not the issue but rather the scope of uniqueness:
>Now, given two log files (log file from day 1 and log file from day 2) we want to generate a list of ‘loyal customers’ that meet the criteria of: (a) they came on both days, and (b) they visited at least two unique pages.
It appears to me that the requirement could be interpreted as either:
"(visit on day 1) AND (visit on day 2) AND (total unique pages count > 2)"
a clearer way to put it would be "visited at least two unique pages in total"
or
"(visit at least two unique pages on day 1) AND (visit at least two unique pages on day 2)"
a clearer way to put it would be "visited at least two unique pages on each day"
