Recently, most div.2 A-D problems disable hack during contest time. However, it turned out that uphack is also disabled for these problems after contest ends.

Sometimes due to the carelessness (which is to some extent unavoidable, as we can't imagine all mistakes that contestants will make and/or all incorrect solutions they might come up with) of the author, the tests will be weak. For example: My solution 353052573 passes system test but there's an obvious bug (The variable dp has type std::map<int, int> instead of std::map<ll, int>), which I realized as soon as I submitted this solution, but it unexpectedly passed all tests.

I suggest that we enable uphack for these problems to maintain the completeness of the test set used in practice. I know that implementing this might need some developing work, but I believe that the Codeforces team is capable of implementing this, and it will be a QOL update for all users.