Seyaua's blog

Codeforces Beta Round #61 (Div. 2)
By Seyaua, 13 years ago, translation, In English
Hello!

I invite you all to take part in significant round! Today will be the first round for second division in Codeforces history, when it will be rated for blue coders!

This time the problems are written by me and sdya. 
We thank Artem Rakhov, Maria Belova and Dmitry Matov for help in preparing of this round.

Good luck for all!

UPD #1: Congrats to Kepnu4, who won the second division and to cerealguy, who won this round!

UPD #2: Link to editorial.
  • Vote: I like it
  • +115
  • Vote: I do not like it

Comments Comments (27)
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13 years ago, # |
  Vote: I like it +4 Vote: I do not like it

YES

First Div 1 : Codeforces Beta Round #39

and now

First Div2 : Codeforces Beta Round #61 (Div. 2)

Good Luck man ..... :D
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13 years ago, # |
  Vote: I like it 0 Vote: I do not like it
Nice problems. Good job , guys
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13 years ago, # |
  Vote: I like it +3 Vote: I do not like it
so many problems were solved with BigInteger....


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  • 13 years ago, # ^ |
      Vote: I like it 0 Vote: I do not like it
    I feel a litlle unfair about D because a solution using BigInteger is too much easier to come up with.
    (I usually use C++ but used ruby to solve D.)

    But thanks for a nice contest! I really had fun.
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    • 13 years ago, # ^ |
        Vote: I like it 0 Vote: I do not like it
      C++ can also solve this problem without a biginteger ...
      you can make the first three number 6 , 10 , 15  and then the numbers follow are 15*2^1 ,15*2^2,15*2^3 and so on
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  • 13 years ago, # ^ |
      Vote: I like it +3 Vote: I do not like it
    That's why CPP programmers must always have their BigInteger codes ready
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13 years ago, # |
  Vote: I like it +1 Vote: I do not like it
  1. if(s.length()<=19)
  2.                   {
  3.                           d=0;
  4.                       for(i=0;i<s.length();i++)d=10*d+int(s[i])-48;
  5.                           if(d<=9223372036854775807LL)cout<<"long"<<endl;else cout<<"BigInteger"<<endl;
  6.                   }else
  7.                           cout<<"BigInteger"<<endl;
  8. Please, tell me why this code work on test "9999999999999999999" (9x19)?
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  • 13 years ago, # ^ |
      Vote: I like it +6 Vote: I do not like it
    Because d is unisgned long long and every number of length <= 19 fits in it
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    • 13 years ago, # ^ |
        Vote: I like it 0 Vote: I do not like it
      Oh, really... I think max value for unsigned long long has 18 digits :(
      Dull mistake. Thx.
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      • 13 years ago, # ^ |
        ← Rev. 2   Vote: I like it 0 Vote: I do not like it
        о_О Приятно увидеть что кого-то мой код всё-таки обманул кого-то :) 
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  • 13 years ago, # ^ |
      Vote: I like it +1 Vote: I do not like it
    There is a very easy way to answer this question using casts.
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13 years ago, # |
  Vote: I like it 0 Vote: I do not like it
twitpic I messed around A due the a quick misinterpretation of minus symbol as dash (hyphen). I request from next time on while writing out negative numbers, don't put a space or linebreak between the minus symbol and the number, so that the negation remains intact and I (lol, just for me) don't get confused. 

:(
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13 years ago, # |
  Vote: I like it +2 Vote: I do not like it
thnx for nice contest :)
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13 years ago, # |
  Vote: I like it -7 Vote: I do not like it

it was a really nice contest...except for problem c that i didn't even try to solve it!!

i actually hate text ones.

thanks every one

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13 years ago, # |
  Vote: I like it 0 Vote: I do not like it
someone has accidentally swapped C and D problems :D
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13 years ago, # |
  Vote: I like it +1 Vote: I do not like it
What's wrong with problem C in these div.2 contests? #57 was just as bad as this one
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13 years ago, # |
  Vote: I like it +1 Vote: I do not like it
loved the contest. thanks for nice contest :).
also, Is it possible to see the test cases ? otherwise can you please share test case #71.
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  • 13 years ago, # ^ |
      Vote: I like it +1 Vote: I do not like it
    forgot to mention for problem C.
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  • 13 years ago, # ^ |
      Vote: I like it +2 Vote: I do not like it
    test case #71 is tricky one. In this test case there are some files with pathes like:
    C:\1\...
    C:\111\...
    If you sort this pathes you obtain bad results.
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13 years ago, # |
← Rev. 3   Vote: I like it +3 Vote: I do not like it
Why each test case is given twice to each code?
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13 years ago, # |
  Vote: I like it +3 Vote: I do not like it
for problem D, 
use 6,10,15, and 6*n (2<=n<= around 60)
can generate the required result
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13 years ago, # |
  Vote: I like it 0 Vote: I do not like it
I feel that contests on codeforces are based a lot on string manipulations which becomes a lot easier for advanced coders who are used to STL data types. At least Div. 2 problems should not have so many questions like that.
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13 years ago, # |
  Vote: I like it 0 Vote: I do not like it
Please use Codeforces.com for linking the names to their profiles in English posts, Thanks.
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