VasuOberoi's blog

ASKING ABOUT HACKS

By VasuOberoi, history, 3 years ago, In English

PROBLEM LINK:https://codeforces.com/contest/1553/problem/B

my solution to this problem got hacked during the contest after it passes the pretests(4).I want to know is there a possibility suppose the hacker didnt hack my solution during the contest and in system testing my solution get accepted because the tests prepared for the question was not good enough or lets say it excludes the test case through which the hacker hacked.??

Also i want to know after somebody succesfully hack other solution do code forces add that particular hack test to their set of tests for system testing or code forces set of tests already has that test case covered.?? please answer

Thanks in advance

  • Vote: I like it
  • -5
  • Vote: I do not like it

»
3 years ago, # |
  Vote: I like it +6 Vote: I do not like it

your code got hacked means it failed a testcase, which other user found so basically, you got WA on that tc. that counts for WA for yo submission

→ Reply
»
3 years ago, # |
← Rev. 2   Vote: I like it +3 Vote: I do not like it

Yes, that particular testcase gets added to the set of testcases. During system testing, all solutions are judged with all testcases (including the ones which successfully hacked a solution).

→ Reply
  • »
    »
    3 years ago, # ^ |
      Vote: I like it +3 Vote: I do not like it

    what about open hacking phase then if going by your comment all custom testcases that hack a particular solution get added and sytem checks for all of the test(including hack tests).Then whats the point for 12 hours hacking phase.So it is bad for the hacker,because the hacker must have hack lots of codes using that particular test if that test case was not added to set of tests

    → Reply
    • »
      »
      »
      3 years ago, # ^ |
        Vote: I like it 0 Vote: I do not like it

      The hacker can hack as many solutions as he/she can during the hacking phase. Once the hacking phase is complete, the system testing phase tests all solutions with all testcases before finalising the ranklist so that no faulty solution gets accepted.

      → Reply