300iq's blog

Invitation to CodeChef May LunchTime 2017!
By 300iq, history, 7 years ago, In English

Hello CodeForces Community,

I take this opportunity to cordially invite you to take part in the CodeChef May Lunchtime. It is an IOI Style contest which will last for 3 hrs.

The problems were set by 300iq (Ildar Gainullin) and tested by adamant (Alexander Kulkov) & Xsquare (Prateek Gupta). The rest of the panel members include:

  • Russian Translator: CherryTree (Sergey Kulik)
  • Mandarin Translator: huzecong (Hu Zecong)
  • Vietnamese translators: VNOI team

We hope you will enjoy the problems and welcome your feedback in the comments below.

Time: Saturday, 27th May, 2017 at 19:30 HRS — 22:30 HRS. (Indian Standard Time +5:30 GMT) Check your timezone here.

Contest link: https://www.codechef.com/LTIME48

Accepted Languages: https://www.codechef.com/wiki/list-compilers

Registration: You just need to have a CodeChef handle to participate. For all those, who are interested and do not have a CodeChef handle, please register here in order to participate.

Prizes: Top 10 performers in Global and Indian school category will get CodeChef laddus, with which the winners can claim cool CodeChef goodies. Know more here: https://www.codechef.com/laddu. (For those who have not yet got their previous winning, please send an email to winners@codechef.com)

Good Luck! Hope to see you participating!!

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7 years ago, # |
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Isn't there a time clash between May LunchTime and Snackdown Pre elimination Round ?

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    7 years ago, # ^ |
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    Snackdown Pre-Elimination Round lasts for 24 hours and the ranklist is based only on problems solved.

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7 years ago, # |
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The queue is ridiculous. My submissions have been running for ages.

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    7 years ago, # ^ |
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    Sorry for that. We are trying to fix it now.

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      7 years ago, # ^ |
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      Is contest being cancelled ?

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        7 years ago, # ^ |
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        If you go to one of your submission you can see this message, so probably yes:

        We are facing issues with the #LTIME48 contest problems and couldn't handle submissions. Keeping SnackDown Pre-Elimination 2017 contest into consideration, we have decided to cancel LTIME48 and make in an unrated contest. The site will now be in read-only mode for sometime. We regret the inconvenience caused.

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        7 years ago, # ^ |
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        here

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      7 years ago, # ^ |
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      Is post tree nlogn or can we do better??

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7 years ago, # |
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Was the solution for the teleport problem something like this:

Rotate the plane so that now we are dealing with squares instead of diamonds. Now whenever we add a new square we add maximum 4 edges with other squares: These edges are to those squares which cover the 4 corners. All other possible squares that overlap will overlap with these.

To find 4 such squares we use some kind of square root decomposition, storing a buffer of queries and then rebuilding after some number of times.

Does this approach work?

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    7 years ago, # ^ |
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    Similar idea but to find 4 squares we can use segment tree with sets and coordinate compression(This is an offline solution).But I feel rotating may give precision errors.

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      7 years ago, # ^ |
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      You can rotate the plane in integers, just change (x, y) to (x — y, x + y).

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        7 years ago, # ^ |
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        I thought of radius becoming √2 times r as possibility of precision error. but now I understand that we cannot avoid the √2 .

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