RAD's blog

By RAD, 10 years ago, translation, In English

Hi everyone!

The recent testing round went well. It is expected that everything will run faster. Today's round was prepared by: Mike Mirzayanov, Nickolay Kuznetsov, Ivan Fefer and Maria Belova.

Good luck!

Artem Rakhov and Codeforces team

 
 
 
 
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10 years ago, # |
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Good luck to everyone!
10 years ago, # |
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okkkkkkkkkkkk

but , please after contest , put PDF of problems similar to past
10 years ago, # |
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2nd one is a little bit confusing.. Especially "If those rules don't indicate the size of the cut are clearly, then the way with which the cut part possesses the largest area is chosen."
10 years ago, # |
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Was the site running extremely slowly or was it just my connection as both have been having their ups and down recently :P
10 years ago, # |
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I have a little question about a challenge case in problem A of today's contest. In my room one coder wrote a subroutine where he checked for every address whether it matches with the "input" string. In order to do that, he run a for loop which checked character by character whether the "input" string matches with any of the addresses. His for loop runs like this:

for ( int i = 0 ; i < input.size() ; i ++ ) {
if(input[i]!=current_address[i]) break;
}

Now my question, shouldn't there be a runtime error when the size of the input is bigger than the current_address, given all the other characters are equal?

I challenged it and it failed. Can anyone explain why?
  • 10 years ago, # ^ |
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    what data type of input && current_address?
    As I know a[big_int] will return 0 if it is string

    upd:
    I tried this code in g++:
    string a("abcde");
    cout<<(int)a[17];

    It prints 0
    • 10 years ago, # ^ |
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      Wouldn't there be an exception?
      • 10 years ago, # ^ |
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        No any exceptions,errors.
        Just 0
        • 10 years ago, # ^ |
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          You are wrong, as far as my tests tell.
          • 10 years ago, # ^ |
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            Can you show me code you are tried?
            And.. language?
            • 10 years ago, # ^ |
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              No problem. I used C++ and string. (as I suppose this is what is used in the solution shown above, though I am not sure).

              So I tried the following:

              int main()
              {
                  string str = "codeforces";
                  cout << str[11] << endl;
                  return 0;
              }

              It banged, crashed, exploded. Still, I agree that if current_address is char[], then the code will not crash and everything will go smoothly, exactly because of the '\0' character you spoke of.
              • 10 years ago, # ^ |
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                do you use MS Visual C++?
                I tried this code:
                #include <string>
                #include <iostream>
                using namespace std;
                int main()
                {
                    string str = "codeforces";
                    cout << str[12] << endl;
                    return 0;
                }
                it runs successful on my computer(g++) and in tab "Run" on codeforces (g++) but crashed in MS C++
              • 10 years ago, # ^ |
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                But '\0' is at str[10], not at str[11]. isnt it?
                • 10 years ago, # ^ |
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                  You are correct, now as I changed the index it really runs smoothly. Cool I did not know that.
  • 10 years ago, # ^ |
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    Can you point to this solution?
  • 10 years ago, # ^ |
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    Hm, if it is char[],first symbol after End of String will 0 too
    • 10 years ago, # ^ |
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      I think the overloaded [] for string object handles it and puts null.
10 years ago, # |
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so, those who are not in div2, were not allowed to open any solution? or it was a problem here? I just wanted to see some people's code (no intention was for hacking :P) but it didn't allow me to do so...
  • 10 years ago, # ^ |
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    you can see and hack solution in your own room( This room consist of users from your division only)
    • 10 years ago, # ^ |
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      that's what I told, no one in my division :p So, I can only open codes from my own division's coders... now it make sense... protect kids from bullies :D
    • 10 years ago, # ^ |
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      hmm, it was a bug, it didn't automatically take me to my room and all I found was div 2 coders.... bad..
10 years ago, # |
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+83   and blue  :D , All effect of "rng"  thanx rng_58.
10 years ago, # |
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Do we get tutorial for this contest?
10 years ago, # |
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In problem B test 7,  the input is 99 100 and the answer is 80 64. But what if the answer is 64 80? My program told me the latter answer and I think it's more reasonable--people would usually like to cut pictures as consistent with the origin ratio as possible, wouldn't they?

  • 10 years ago, # ^ |
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    Read carefully problem statements. Tiebreaker is maximal height. Only statements is source of logic in programming contests.
    • 10 years ago, # ^ |
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      Yes you're right. I didn't notice it.