@admin From October challenge, the challenge problem will be judged during contest only on 20% of the test cases. (see this).However is it guaranteed that passing these test cases(20%) also means that our code will pass remainder of the test cases?
It will be really frustrating solving a question for 2-3 days and then getting TLE or some other error on the remainder of the test cases if they are judged later.
One thing i would suggest is run the code on all test cases but show the score for only for 20% of test cases. The advantage of this will be that people will know before hand if their code gets accepted or rejected for all test cases before the contest gets over while the purpose of showing score on only 20% of test cases is also maintained.