Codeforces celebrates 10 years! We are pleased to announce the crowdfunding-campaign. Congratulate us by the link https://codeforces.com/10years. ×

jonathanirvings's blog

By jonathanirvings, history, 23 months ago, In English,

Google Code Jam 2018 Practice Round has just been opened. It will be open for 48 hours.

Go to https://codejam.withgoogle.com/2018/ to check out our new competition platform :)

 
 
 
 
  • Vote: I like it
  • +56
  • Vote: I do not like it

»
23 months ago, # |
  Vote: I like it +12 Vote: I do not like it

The C++ code gets compiled with g++ -std=c++11.

  • »
    »
    23 months ago, # ^ |
    Rev. 2   Vote: I like it +90 Vote: I do not like it

    I was eagerly waiting for the new platform for distributed code jam, because I expected I could use C++14 with it at last. Here comes the new platform (for regular code jam) and it still has only C++11, while (awesome) C++17 is already out there. OK, Google, seriously? I was really hoping that only TopCoder is so lazy and behind the times not to update the compilers, and I can ignore it, but no.

  • »
    »
    23 months ago, # ^ |
      Vote: I like it +57 Vote: I do not like it

    The funniest thing is that if they didn't force any version, it would be defaulted to c++14

»
23 months ago, # |
  Vote: I like it +9 Vote: I do not like it

Woah, the new UI looks Awesome! <3

»
23 months ago, # |
  Vote: I like it +120 Vote: I do not like it

I have to admit that I don't like the new interface.

  • The problems tab is missing problem statistics and the current rank.
  • The scoreboard is also missing problem statistics and there is no friends feature or any other way to find out how a specific user is doing.
  • There is no button to upload source code from a file and the editor on the page does not support pasting via middle mouse button, which makes submitting code tedious for me.

On the other hand I am really looking forward to some creative interactive problems in GCJ 2018.

  • »
    »
    23 months ago, # ^ |
      Vote: I like it +45 Vote: I do not like it

    and no flags T_T

  • »
    »
    23 months ago, # ^ |
      Vote: I like it +79 Vote: I do not like it

    Another issue is that the submission language defaults to bash, and submitting a program in another language only results in a runtime error.

    • »
      »
      »
      23 months ago, # ^ |
        Vote: I like it +33 Vote: I do not like it

      Also, in the old format, an output not respecting the format did not trigger a penalty, which is another source for new penalty.

      All information about the faulty test case has also disappeared in case an answer fails.

  • »
    »
    23 months ago, # ^ |
    Rev. 2   Vote: I like it +22 Vote: I do not like it

    Also there's no way to download submitted source code (as far as I see).

  • »
    »
    23 months ago, # ^ |
      Vote: I like it +15 Vote: I do not like it

    I think I saw a button to select a file right next to the Submit button in the editor.

    But I also dislike this overall.

»
23 months ago, # |
  Vote: I like it 0 Vote: I do not like it

Input format?

»
23 months ago, # |
  Vote: I like it +53 Vote: I do not like it

Heads up to people submitting in Java: your class has to be named Solution otherwise you get a runtime error.

»
23 months ago, # |
  Vote: I like it -59 Vote: I do not like it

Is it rated?! :-o :D

»
23 months ago, # |
  Vote: I like it +60 Vote: I do not like it

Small and Large datasets run for the same source ? We can't upload different sources for each one, cause I don't see any option like that ? If that happens, this can change a lot of things in strategy. Some people were submitting small dataset very fast and after they were spending some time to large dataset. Now if someone spends time for large dataset and eventually his submission fails, he will take less points than an other one who has submitted faster a source just to pass the small dataset.

  • »
    »
    23 months ago, # ^ |
      Vote: I like it +22 Vote: I do not like it

    I don't exactly remember the new scoring rules, but I guess your score is one of two following, whichever is better:

    • the last submission, and
    • the submission which passed the most "small" datasets (however, you cannot score for "large" datasets here).

    Now, if you sent two submissions, the former passing the small dataset and the latter failing to pass anything, you'd still be awarded points for the small dataset. (Please correct me if I'm wrong.) I think it's still profitable to submit your programs for "small" dataset(s) first, and then fight for the "large" one(s).

    • »
      »
      »
      23 months ago, # ^ |
        Vote: I like it +30 Vote: I do not like it

      Yes, you are right. But still I think there are some differences. In old contests you had no penalty if you would submit two times, one time for small dataset and one time for big dataset, but here you have penalty. So lets say, user1 submits two times (1st at 5min(small), 2nd at 10min(larget)) and user2 submits one time (at 10min(both small and large))

      then in old contest rank would be user1 >= user2, but now we have user2 > user1.

      • »
        »
        »
        »
        23 months ago, # ^ |
          Vote: I like it +14 Vote: I do not like it

        Oh, you're absolutely right. Yup, it changes things a bit.

»
23 months ago, # |
  Vote: I like it 0 Vote: I do not like it

who is going to write a parser for problem stats? :D

»
23 months ago, # |
  Vote: I like it +45 Vote: I do not like it

I can't download my solution. I can't see scores of my friends. What's next?

  • »
    »
    23 months ago, # ^ |
      Vote: I like it +41 Vote: I do not like it

    April fool

  • »
    »
    23 months ago, # ^ |
      Vote: I like it +22 Vote: I do not like it

    No country flags. No way to submit for small/large datasets only. No C++14.

    Why would they create a worse application for that LOLLL

»
23 months ago, # |
  Vote: I like it +258 Vote: I do not like it

Here is a list of feature requests (some of them are already mentioned above), in the order of importance in my sense.

  • We don't know how fast the judge server is, and we may want to use "Custom Test" (i.e., run a program on the judge server and measure the time). This is especially important in "System Test" style contests.

  • Since we don't manipulate files anymore, we don't really need to put multiple cases into a single file. It will be more convenient if each input contains a single testcase (and don't print things like "Case #").

  • We may get penalties for stupid reasons. For example choosing incorrect language, forgetting "Case #", etc. One possible way to avoid this is to prepare a sample input that satisfies the constraints of SMALL, and ignore submissions that don't pass the sample.

  • Friends, flags, search users, etc. It will be nicer if you raise the limit of the number of friends.

  • We can show sample input/output even for interactive problems, like http://codeforces.com/gym/101021/problem/A. Personally this is easier to read than pseudo code.

  • We may want to read solutions we sent before.

By the way, until last year GCJ used "optimistic standings" (because some submissions for LARGE may fail), but now GCJ uses "extremely optimistic standings". Even when someone sends a solution just for SMALL, in the standings it's considered as a correct submission for LARGE. From the standings we will get almost no information about the difficulties of LARGE.

  • »
    »
    23 months ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    Since we don't manipulate files anymore, we don't really need to put multiple cases into a single file. It will be more convenient if each input contains a single testcase (and don't print things like "Case #").

    Not really — if the solution is simple (e.g. a formula) then starting up process takes orders of magnitude more than the solution itself, which restricts total number of tests significantly.

    • »
      »
      »
      23 months ago, # ^ |
        Vote: I like it +56 Vote: I do not like it

      Yes, but I think such problems are kind of exceptions. We can use a single case in majority of problems, and multiple cases in such problems.

  • »
    »
    23 months ago, # ^ |
      Vote: I like it +20 Vote: I do not like it

    A "Custom Test" is badly needed. I was getting WA in the contest in one of the problems but the solution was running fine on my local machine. Just chancing "double" to "long double" gave AC.

  • »
    »
    23 months ago, # ^ |
      Vote: I like it +19 Vote: I do not like it

    please also send this to their email, I'm afraid they will ignore it anyway, but here they probably won't even read it.

»
23 months ago, # |
  Vote: I like it +48 Vote: I do not like it

This seems like a good contest, but its NOT codejam. Codejam was the best contest ever! I hate the new format, the new interface, really don't understand why Google changed everything.

»
23 months ago, # |
  Vote: I like it +5 Vote: I do not like it

My submission for the small sample of A is Correct, but appears as "Skipped" for Large Sample. Did this happen to anyone else?

  • »
    »
    23 months ago, # ^ |
      Vote: I like it +10 Vote: I do not like it

    Yes to me. It seems as "skipped" but in the scoreboard it says "Solved". Also for last problem, largest dataset in the scoreboard says "Not solved" but in problem section says "The judgment was skipped". Weird ...

    • »
      »
      »
      23 months ago, # ^ |
      Rev. 3   Vote: I like it +3 Vote: I do not like it

      Yeah, it also appears this way for the problem B on my side (but it is counted in my score)

      I guess both A and B were actually tried, but A didn't pass, for a reason I cannot see that is not "Skipped" (nor can I see the solution I sent). The only problem that my solution could have would be sending guesses higher than B, which might be causing an error, but nothing was specified in the problem (although after rereading I admit it might have been alluded to).

      So there is an inconsistency between the scoreboard and the problem section, I hope everything will be fixed for the real competition.

  • »
    »
    23 months ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    I can't find the link to the problems or check my submissions. Can you provide it?

»
23 months ago, # |
  Vote: I like it 0 Vote: I do not like it

I’m guessing Python is not PyPy then. But I can’t easily check, because the language list doesn’t say which implementation it is and there’s no way to see the output of my submissions! Also I can no longer use things like ordered sets that aren’t in the standard library… (unless they’re specifically installed on the server, but there’s nothing to suggest this).

  • »
    »
    23 months ago, # ^ |
      Vote: I like it +5 Vote: I do not like it
  • »
    »
    23 months ago, # ^ |
    Rev. 2   Vote: I like it +16 Vote: I do not like it

    As someone who usually competes using pypy the new google system is basically unusable, pypy is in many cases needed to make python run quick enough. This is the first time competition I've seen not allowing pypy. I'm not impressed.

  • »
    »
    23 months ago, # ^ |
      Vote: I like it -10 Vote: I do not like it

    Forgot to check it during the practice session, but does it support networkx? It would otherwise be disastrous to solve bipartite graph matching.

»
23 months ago, # |
  Vote: I like it +77 Vote: I do not like it

MakeGCJGreatAgain

»
23 months ago, # |
  Vote: I like it 0 Vote: I do not like it

Does anyone know what makes the Number Guessing large fail? It shows "The judgement was skipped." on the side while it's "Not solved." on scoreboard. Is that an issue on the stdin stdout or binary search just does not work for large?

  • »
    »
    23 months ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    In my solution, it might be that I try to do a naive binary search starting at the highest significant binary digit of B.

    Thus, in some test cases, it probably guesses a number higher than B, which according to the problem can be "WRONG_ANSWER".

    If your program gets something wrong (e.g., wrong output format, or out-of-bounds values) the judge will send WRONG_ANSWER

    Even if they don't explicitely define what 'out-of-bounds' means for a guess, it might be that no guess can be greater than B.

»
23 months ago, # |
  Vote: I like it 0 Vote: I do not like it

On this screenshot it says that "The judgement was skipped" for the large input. However in the scoreboard it says that I got correct answer on that test.

I think that giving an approximation of how long the queue is for judgement would be a relevant idea. Just writing stuff like "Compiling...", "Running...", would already be enough in my opinion. Writing the number of submissions that are in queue would be even better. :D

Also, where can I see the number of people that attempted/solved a given problem?

  • »
    »
    23 months ago, # ^ |
      Vote: I like it -23 Vote: I do not like it

    Can you share your accepted solution Plzz as the contents is over but there is no link to see the solution Plzz

»
23 months ago, # |
  Vote: I like it -23 Vote: I do not like it

Hello Everyone! I had taken part in practice round I tried very much but my solutions for 1 and 2nd questions where not accepting it was giving TLE there was some problem in inputs CAN PLZZ ANYONE CAN SHARE THERE 1ST AND 2ND SOLUTION PLZZ

»
23 months ago, # |
  Vote: I like it +10 Vote: I do not like it

If we have found solutions post contest, how/where can we submit the codes to verify correctness?

»
23 months ago, # |
  Vote: I like it 0 Vote: I do not like it

I am trying to submit my code for "Trouble sorting" but constantly getting "An error occurred. Please try again later." Anyone encountered the same issue?