Earlier quoted context omitted.
"They memorized all the problems" is not what was found here and still a wrong overcorrection.
If you are shown only the title of a coding problem and the site name where it's from, and you manage to solve it you are showing that you either cheated or knew the answer.
The key is, can you guess the problem from the title and the function name? I'd argue, sure, at least half the time?, why not...