csacademy's blog

Round #12 (Div. 2)
By csacademy, 8 years ago, In English

Hello, Codeforces!

We are happy to announce that we're going to host a new contest at csacademy.com. Round #12 will take place on Thursday, September/15/2016 16:00 (UTC). This round will be a Div. 2, meaning that the rating change will only affect users with a rating below 1550. Unrated users will also be affected. High rated coders can participate unofficially.

If you want to take part in this round you need to register before the contest begins. Unlike the previous rounds, this will be Div. 2. It will consist of 5 tasks of more accessible difficulty.

Many thanks to Yury_Bandarchuk for translating the statements in Russian!

Platform changes since Beta Round #11:

  • Worked on improving the platform stability.
  • The workspace now works even if you are not logged in.

Contest format:

  • You will have to solve 5 tasks in 2 hours.
  • There will be full feedback throughout the entire contest.
  • Tasks will not have partial scoring, so you need to pass all test cases for a solution to count (ACM-ICPC-style).
  • Tasks will have dynamic scores. According to the number of users that solve a problem the score will vary between 100 and 1000.
  • Besides the score, each user will also get a penalty that is going to be used as a tie breaker.

About the penalty system:

  • Computed using the following formula: the minute of the last accepted solution + the penalty for each solved task. The penalty for a solved task is equal to log2 (no_of_submissions) * 5.
  • Solutions that don't compile or don't pass the example test cases are ignored.
  • Once you solve a task you can still resubmit. All the following solutions will be ignored for both the score and the penalty.

We still recommend using an updated version of Google Chrome. If you find any bugs please email us at [email protected]

Don't forget to like us on Facebook, VK and follow us on Twitter.

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8 years ago, # |
  Vote: I like it +3 Vote: I do not like it

When i visit csaacademy.com , all I see is a blank page . In both Chrome and Firefox .

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    8 years ago, # ^ |
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    Same here !!

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      8 years ago, # ^ |
        Vote: I like it +6 Vote: I do not like it

      For me, the load time is a little high (~4-5sec) on the mainpage the first time you access it, but the website works fine.

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

Can somebody explain the approach for this problem : https://csacademy.com/contest/round-12/#task/bitwise-and-queries thank you :)

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    8 years ago, # ^ |
    ← Rev. 3   Vote: I like it +1 Vote: I do not like it

    my approach :

    suppose we have 63 bits. for each a,b,x. find bits in x that are 0 ( call them empty ). cnt = number of 0's in x.

    x -> do binary search on [ 0 , 1<<cnt ]. in BS put current number bits in empty places of x and compare it with a ( you must find lowest number such that is >= a )

    y -> do another binary search on [ 0 , 1<<cnt ]. in BS put current number bits in empty places of x and compare it with b ( you must find lowest number such that is > b )

    ans = y — x

    for better understanding, check my code. note that we can do better than this , check the editorial.

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

How to solve E ?

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