@PsychoKiller These are really valuable feedback! Thank you so much for sharing them.
Could you please let me know which specific language option of C/C++ did you use where you saw gets() working? Ideally, what you said, is correct. gets() is not standard and should not be allowed. However, it is possible that for certain C/C++ option, the GNU C/C++ compiler allows it. It depends on what parameters we pass to the compilers when we process your submissions.
We have a page where we share the details about the programming languages we support and the compiler options we use. You can find the page here: Languages | Toph.
I will still look into this and add some notes to the languages page as necessary.
We have always received mixed reactions regarding quotes shown on the loading screen. Personally, I am indifferent about it. However, since I think there is a considerable number of users who do not like it, we will remove it in the next couple of days.
Custom invocation is something we have in mind. This is something we would however want to get to later this year as at this moment our focus is to improve stability and performance over all things. Some of the new features will then have to wait a little.
The issue with the test button not working for interactive problems has to do with the fact that the problem didn’t have any sample test case. The example case you saw was just text added at the end of the Output specification section:
And the bug is that when there are no sample test cases for a problem, the Test button is effectively broken. This is something we might not have discovered immediately unless you had brought it to our attention, so thank you for that! We really appreciate it.