csacademy's blog

Round #33 (Div. 2) + Special Prizes
By csacademy, 7 years ago, In English

Hello, Codeforces!

We are happy to announce that we're going to host a new contest at csacademy.com. Round #33 will take place on Wednesday, June/14/2017 15:00 (UTC). This round will be a Div. 2, meaning that the rating change will only affect users with a rating below 1675. 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. As this is a Div. 2, it will consist of 5 tasks of more accessible difficulty.

Special prizes

This round will have 3 special prizes consisting of private coaching lessons with our contest coordinator, wefgef. Each lesson will be conducted on Skype and will last for 1 hour and 30 minutes. The topics approached during the lesson will be the choice of the winners. The prizes will be distributed as follows:

  • 1 random prize for the top 20%
  • 1 random prize for the next 30%
  • 1 random prize for the bottom 50%

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.

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  • Vote: I like it
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7 years ago, # |
  Vote: I like it +12 Vote: I do not like it

Just a reminder, the contest starts in 4 hours.

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7 years ago, # |
  Vote: I like it +14 Vote: I do not like it

Why is the border of div2 constantly changing? It is being recalced after each contest? Is every color border being recalced?

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7 years ago, # |
  Vote: I like it +4 Vote: I do not like it

Can someone please explain D's editorial in a bit more detail? More specifically, what do the points in the final stack represent? And what is the condition for popping a particular point from the stack?

I had trouble understanding the following statement — "This happens if the moment when the new point becomes closer to the segment when compared to the top of the stack comes before the moment when the top of the stack becomes closer when compared to the previous point in the stack."

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    7 years ago, # ^ |
    ← Rev. 2   Vote: I like it +8 Vote: I do not like it

    I think it is similar to convex hull trick. U find the point of intersection of perpendicular bisector of point and top of stack with x axis. If that is before active region(left coordinate) of top of stack. then the point on top of stack is useless. This can be proven by induction using the fact that point at (infinity,0) is always closer to the one with highest x coordinate.

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

This username is reserved for Codeforces user with this handle. To claim it link your Codeforces account in External accounts tab.

Why nothing happened after sending such token? How to set my username?

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