MikeMirzayanov's blog

Codeforces Testing Round #1
By MikeMirzayanov, 13 years ago, translation, In English

Hello!

Tired to rest? Your help is needed.

During the period from December 31 until today I have made many changes in the Codeforces. The changes affected only the interior, so you will not notice any change in the user interface. Nevertheless, during this time was changed about 150 project files, database schema, some principles of data storage. In short, after all this, I'm not sure that everything works as expected (although, of course, I spent time on testing). For this reason I decided to organize Codeforces Testing Round #1, which will unrated and his only goal - a comprehensive testing of the project in conditions close to the real contest.

It will be three problems (possibly well-known, folklore), but I hope it will be pleasure to solve them.

Thanks for the help to Artem Rakhov, Maria Belova, and Max Ivanov

MikeMirzayanov.

UPD: Thanks to all. The round finished. We didn't notice any bugs. Write suggestions and opinions in the comments.

Announcement of Codeforces Testing Round 1
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  • +49
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Comments Comments (31)
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13 years ago, # |
  Vote: I like it +24 Vote: I do not like it
so many thanks by the improvements. .the site is growing up!
and I would like to do some comments:
some time ago, when I entered in a ended contest and check MY SUBMISSIONS there were two columns: my submissions and my contest submissions but now there appear my submissions twice..
and I would like to see  the search bar againg, because sometimes I see a nice post but when I try to find it again I can't .
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  • 13 years ago, # ^ |
      Vote: I like it +7 Vote: I do not like it
    Thank you. Fixed. It is the exactly feedback I'm waiting from you. It was a side effect of the status caching.
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13 years ago, # |
  Vote: I like it +5 Vote: I do not like it
I've submited only one solution to task b which passed pretests and I have gray -1 at this column before it is judged on systests.
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  • 13 years ago, # ^ |
      Vote: I like it 0 Vote: I do not like it
    Later I noticed, that my solution wasn't in queue, but had status pretests passed.
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13 years ago, # |
  Vote: I like it 0 Vote: I do not like it
Hello, I found that in "my submissions" page A submission was "in queue" and B submission was "pretests passed" when they both were in queue. About five minutes before the contest end I could not see others' solutions. However, that was successful in the middle of the contest.
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  • 13 years ago, # ^ |
      Vote: I like it +5 Vote: I do not like it
    I think five minutes before the end of the contest, the Codeforces server was down. I could not open any other problem during this time nor see other codes even after locking my solution. Rest of the contest was fine.
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13 years ago, # |
  Vote: I like it +5 Vote: I do not like it
Ok, a short and funny contest at the beginning of the year.

I'm learning Python recently, so I try to write Python code today.
But it seems too slow to pass.

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  • 13 years ago, # ^ |
      Vote: I like it +4 Vote: I do not like it
    But you're cgy4ever!! How could you let yourself use Python?
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  • 13 years ago, # ^ |
      Vote: I like it +1 Vote: I do not like it
    Me too, and I was not sure whether my B will pass; but it did!

    Of course it's risky to solve common contest problems in interpreted languages: a few million simple operations could easily time out.
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13 years ago, # |
  Vote: I like it 0 Vote: I do not like it
I could not understand. Why the following code did not pass the system test?
System says "time limit exceeded on test 18". There is only one loop and it is to input numbers that's all.
Plus one loop from 1 to 3, which does not add much time..


import java.util.*;
public class T1 {
    public static void main(String args[]){
        Scanner sc=new Scanner(System.in);

        int n=sc.nextInt();
        int a[]=new int[4];

        for(int i=0;i<n;i++){
            a[sc.nextInt()]++;
        }
        int max=-2;
        for(int i=1;i<=3;i++){
            if(a[i]>max)
                max=a[i];
        }
       
               System.out.println(n-max);

    }//main
}//class
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  • 13 years ago, # ^ |
      Vote: I like it 0 Vote: I do not like it
    Scanner reads numbers to slow. You should use faster methods like BufferedReader and StringTokenizer.
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  • 13 years ago, # ^ |
      Vote: I like it +1 Vote: I do not like it
    Scanner is very slow.
    Use BufferedReader+StringTokenizer+Integer.parseInt instead.
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13 years ago, # |
  Vote: I like it 0 Vote: I do not like it
many thanks..
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13 years ago, # |
  Vote: I like it 0 Vote: I do not like it
At my submissions for problem A, each test is printed twice - with the verdict and all that
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13 years ago, # |
  Vote: I like it 0 Vote: I do not like it
Is there a way to see the hacks done by other participants?
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13 years ago, # |
  Vote: I like it 0 Vote: I do not like it
I think you can add "remove message" option. It would be good to delete all junk messages.
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  • 13 years ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    For private messages - yes.

    For threads - probably shouldn't.

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13 years ago, # |
  Vote: I like it 0 Vote: I do not like it
didn't receive an email before the contest .
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13 years ago, # |
← Rev. 2   Vote: I like it 0 Vote: I do not like it
I can't see the problem #43's A.
The page display just "RPC call for action failed."
Is it bug?
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13 years ago, # |
  Vote: I like it 0 Vote: I do not like it
I am not able to open http://codeforces.com/contest/50/problem/C (this is problem C from contest 47) it says:
RPC call for action failed.
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  • 13 years ago, # ^ |
      Vote: I like it 0 Vote: I do not like it
    Sorry just saw other users complained about similar problems.
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13 years ago, # |
  Vote: I like it 0 Vote: I do not like it
Any chance to get official analysis/solutions of the problems in this round? Especially problem C? :D
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  • 13 years ago, # ^ |
      Vote: I like it +3 Vote: I do not like it
    It's solved with strandart Segment_tree. Ask if needed more information.
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    • 13 years ago, # ^ |
        Vote: I like it 0 Vote: I do not like it
      I have never written nor used a segment tree, so any additional information regarding the implementation and main idea of the problem would be very welcome.
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      • 13 years ago, # ^ |
        ← Rev. 2   Vote: I like it 0 Vote: I do not like it
        Everything you need is here. The only 'non-standard' thing is that RMQ in the problem is circular, but since any 'wrapping' segment can be divided into two 'unwrapping' ones, this is not really an issue.
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        • 13 years ago, # ^ |
            Vote: I like it 0 Vote: I do not like it
          I read the TopCoder article you specified and wrote a solution accordingly, but I get TLE on test case 8. :(

          Would anyone be willing to have a look at my code and show me what I am doing wrong?
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