MikeMirzayanov's blog

Codeforces Beta Round #95 (Div. 2)
By MikeMirzayanov, 13 years ago, translation, In English

Hello!

On Friday, November 25 at 19:00 I'm waiting you on the Codeforces Beta Round #95 (Div. 2). This round is prepared by me. It is not easy to prepare a round, but it is always useful and interesting. By my example, I want to hint to top participants that rounds of famous people — it's always interesting!

Apart from me RAD, Nickolas and Delinur were doing work on the round. Moreover, Edvard still do not know, but very soon I will ask him to solve this round as a tester:)

It will be unusual round because you will find six problems. It's a little experiment — I hope that it will help each participant to find interesting problems to themselves.

I believe that the out-of-competition participants from Div.1 will have some fun solving the round.

The problem scoring is: A - 500, B - 1000, C - 1500, D - 2000, E - 2500 and F - 2500.

Good luck!

MikeMirzayanov

UPD. The competition has ended. Here are the results. First place was taken by the representative of China — liuq901. Congrats! It was nice to see such interest to the contest. Thank you for your participation!

Unfortunately, I do not have the opportunity to write a tutorial. If you deal with it I will be grateful.

  • Vote: I like it
  • +75
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Comments Comments (52)
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13 years ago, # |
  Vote: I like it +12 Vote: I do not like it
For Div 1 participants, I hope you'll not make cloning ID :P
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13 years ago, # |
  Vote: I like it +4 Vote: I do not like it
What will be the Rating system for 6 problems???
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  • 13 years ago, # ^ |
      Vote: I like it +1 Vote: I do not like it
    And what about the difficulty, will the sixth problem be more difficult than fifth in usual round?
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13 years ago, # |
  Vote: I like it +3 Vote: I do not like it
What will be the POINT distribution of those 6 Problem  ??
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13 years ago, # |
  Vote: I like it +5 Vote: I do not like it
In the email it says that the round is for DIV-2 i.e. anyone below 1650 rating. What is the division cut rating? I thought it was 1700 after the recent color changes...?
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  • 13 years ago, # ^ |
      Vote: I like it 0 Vote: I do not like it
    In my email I got that too.
    But it should be 1700.
    Unfortunately Officials may missed that point.
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  • 13 years ago, # ^ |
      Vote: I like it 0 Vote: I do not like it
    I am also confused. The cut rating is still the same as before or may be it was a mistake?
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    • 13 years ago, # ^ |
      ← Rev. 2   Vote: I like it +1 Vote: I do not like it

      In the "registered" page it shows You are registered as [out-of-competition].

      But it shouldn't be.
      Because in Rating Distribution Table MikeMirzayanov wrote that all BLUE(1500-1699) are in Div2.

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    • 13 years ago, # ^ |
        Vote: I like it 0 Vote: I do not like it
      So don't be confused.Its just an ADMIN fault.Nothing else.
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      • 13 years ago, # ^ |
          Vote: I like it 0 Vote: I do not like it
        I dont see any lines by Admin where it stated clearly that all blue are in div 1. @Admins: Please resolve the confusion.
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        • 13 years ago, # ^ |
            Vote: I like it 0 Vote: I do not like it
          Check the table carefully.
          I didn't said "all blue are in div 1" I said "all BLUE(1500-1699) are in Div2"
          Because while seeing table you will see ->
          Ratings RangeColorTitleDivision
          2600+RedInternational grandmaster1
          2200 - 2599redGrandmaster1
          2050 - 2199OrangeInternational master1
          1900 - 2049OrangeMaster1
          1700 - 1899VioletCandidate master1
          1500 - 1699BlueExpert2
          1350 - 1499GreenSpecialist2
          1200 - 1349GreenPupil2
          0 - 1199GrayNewbie2
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  • 13 years ago, # ^ |
      Vote: I like it 0 Vote: I do not like it
    Same question.
    → Reply
13 years ago, # |
  Vote: I like it +2 Vote: I do not like it
Six Problem ? there is one more easier or harder problem?
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13 years ago, # |
  Vote: I like it 0 Vote: I do not like it
Can someone please tell me why nC4*mC1*(n+m-5)C(t-5) wrong for the problem c....
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  • 13 years ago, # ^ |
    ← Rev. 5   Vote: I like it +2 Vote: I do not like it

    Nevermind

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  • 13 years ago, # ^ |
    ← Rev. 2   Vote: I like it +1 Vote: I do not like it

    Try 4 2 6.


    your answer will be C(4, 4) * C(2, 1)  * C(1, 1) = 2, but actually t = n + m, so there's only one way.

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13 years ago, # |
  Vote: I like it 0 Vote: I do not like it
I don't like 6-problems Codeforces round.
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  • 13 years ago, # ^ |
      Vote: I like it +5 Vote: I do not like it
    Why?
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    • 13 years ago, # ^ |
        Vote: I like it +2 Vote: I do not like it
      In my opinion it is too much for rounds like Codeforces. It is better to give less number of problems rather than more problems (and more coding/less thinking), even for div2 users.

      But, of course, as experiment it was great.
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  • 13 years ago, # ^ |
      Vote: I like it +50 Vote: I do not like it
    Want seven?
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  • 13 years ago, # ^ |
      Vote: I like it +4 Vote: I do not like it
    I agree with you. Six problems are too mach for 2 hours. Both five and four are OK.
    → Reply
13 years ago, # |
← Rev. 2   Vote: I like it +4 Vote: I do not like it

I liked the idea of 6 problems, but i think problems were easy , it should be a little difficult or the old format of contest must be chosen. :)

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13 years ago, # |
  Vote: I like it +3 Vote: I do not like it
First time I solved 5 problems :)
But I failed E because of too little array size (105 instead of 2*105). Very disappointing bug :|
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13 years ago, # |
  Vote: I like it +5 Vote: I do not like it
To Admins ,
When i'm taking my hacking tour i open source code of contestant and i found Indecent words on his\her code in problem "B" Moreover his handle name is
I know this is not the right place to report about this cases but i didn't found any way rather than this.
btw,I hacked his/her problem #"A".and this is my punishment ,what about admins punishment.
thanks.
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  • 13 years ago, # ^ |
      Vote: I like it 0 Vote: I do not like it
    Nice guy, he is my friend now :) penis is a good word, what would you do without a penis?
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    • 13 years ago, # ^ |
        Vote: I like it -14 Vote: I do not like it
      maybe he had in mind "member", but accidentally write "penis"?
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      • 13 years ago, # ^ |
          Vote: I like it 0 Vote: I do not like it
        FYI, this doesn't make any sense to non-Russian speakers.
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        • 13 years ago, # ^ |
            Vote: I like it 0 Vote: I do not like it
          I don't think so, this word also means "limb", "detail", it is not so common, but it make sense.
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        • 13 years ago, # ^ |
            Vote: I like it 0 Vote: I do not like it
          Yes it is. I read a lot of novels in English lately and that was one of quite a few discoveries I made (other one, for expample, that breakfast has nothing to do with 'quick' meaning of fast)
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  • 13 years ago, # ^ |
      Vote: I like it +11 Vote: I do not like it
    Any complains on cheating, indecent behavior etc. should be sent to admins via "private messaging".

    Pitifully administration of codeforces does not usually perform any censorship for such cases, though obviously such behavior of contestants is a kind of offending one.
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  • 13 years ago, # ^ |
      Vote: I like it 0 Vote: I do not like it
    why you complaining if the system test still give him Accepted :P
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  • 13 years ago, # ^ |
      Vote: I like it -6 Vote: I do not like it
    And? It's his code!
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13 years ago, # |
  Vote: I like it 0 Vote: I do not like it
weak pretest :-( failed 3/6
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  • 13 years ago, # ^ |
      Vote: I like it 0 Vote: I do not like it
    Div2  contest , there are fewer hacking attempts than div1, so i think stronger pretest will be more proper.
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13 years ago, # |
  Vote: I like it +8 Vote: I do not like it
Wait, next contest is on 

19:00 Moscow time

why it must on 07.00 PM, it's like 22.00 PM in my country every contest. .
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  • 13 years ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    It is start at 23:00 PM in China,I think it's not equitable for us.  Why can't  we start early?

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13 years ago, # |
  Vote: I like it +13 Vote: I do not like it
This is really a nice problem set. Thank you MikeMirzayanov. :)
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13 years ago, # |
  Vote: I like it +12 Vote: I do not like it
Will anyone take the trouble of writing the editorials(especially for D,E,F) since Mike Mirzayanov cannot to it for some reasons...It will be very obligatory deed.
Another thing is that codeforces is taking editorials very lightly...There should be one tab for editorials like problemset.....It sometimes becomes very difficult searching for the editorials.That should add more value to the site.
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  • 13 years ago, # ^ |
      Vote: I like it +2 Vote: I do not like it
    If nobody will write an editorial, I can write at least some outlines of the solutions I did...
    Also, I agree with the "Editorials" tab. It would be very handy.
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    • 13 years ago, # ^ |
        Vote: I like it 0 Vote: I do not like it
      There's a post with editorials. I think it would be great to make the link to it from the main page.
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  • 13 years ago, # ^ |
      Vote: I like it 0 Vote: I do not like it
    I just noticied that vexorian has posted in his blog.
    I've posted some ideas in my blog, before noticing that...
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    • 13 years ago, # ^ |
        Vote: I like it 0 Vote: I do not like it
      My blog post was made in an absurd fast time and is not as complete as yours (fewer details, does not have F), so there's no problem.
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13 years ago, # |
  Vote: I like it 0 Vote: I do not like it
Did anyone else also feel problem A was not really clear? I got 3 penalties in that. :(
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13 years ago, # |
  Vote: I like it 0 Vote: I do not like it
The First place liuq901 make 5 successful Hacks and 3 unsuccessful Hacks but 
system wrote s\he make 5 successful Hacks and 2 unsuccessful Hacks
what's the wrong ???.
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13 years ago, # |
  Vote: I like it 0 Vote: I do not like it
Can anyone give some hints on how to solve Prob. F ??
thx a lot!
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3 years ago, # |
← Rev. 2   Vote: I like it 0 Vote: I do not like it

great

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    3 years ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    Your necropost isn't so great.

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      3 years ago, # ^ |
      ← Rev. 2   Vote: I like it 0 Vote: I do not like it

      How did you even find me man, but touche. I thought there was a mistake in the test then I realized I was too high on weed and swapped jury's answer for mine. Thus I editted comment into 'great', knowing I cannot delete it. Now, you can do us a favor and go to sleep.

      → Reply