Is it possible to create new test cases for practice problem.

betlista · July 13, 2012, 7:33pm

I fully understand that it might happen that there is not worst case test case for all algorithms solving the problem. Also I’m not a fan of changing the test cases during the contest. But I think that I’s good idea to maintain test cases in practice room to be as good as possible.

Few examples:

problem Next Palindrome, test cases are incorrect, instead of palindrome greater than N it checks palindromes greater or equal to N
weak test cases for Remember the recipe, were discussed at editorial page
actually brute force approach got AC in The Gray-Similar Code

Is it possible to create test case and rejudge all submissions for some problem in practice room?

I can imagine more difficult process: specifying also the solution I’d like to challenge and if it is correct challenge, then all submissions will be rejudged.

admin · December 4, 2012, 5:00pm

Yes. But this involve getting the test data verified by the problem setter which may not even be possible for the old problems.

Please send us the test data to mailto:problems@codechef.com and we shall try and get them added to the problem and rejudge all the submissions.

betlista · December 5, 2012, 3:26am

perfect, thanks for your answer

anton_adm · December 5, 2012, 4:18am

In fact, there are several technical complications. The solutions from the actual contests can not be rejudged in any way or it may ruin results of the contest and sometimes even top may change. So in rejudge tool we should carefully set limits for submissions IDs that should be rejudged. And it could be very dangerous since mistyping just one digit could touch solutions from the contests. Of course we can revert test sequence back and rejudge again but in any case it is quite unpleasant procedure.

admin · July 21, 2013, 11:19pm

The rejudge will only happen on the practice section and not for the contests. The test data can only be added to the problems in the practice section.