prophet_ov_darkness's blog

[GYM] 2018 BACS Contest Replay
By prophet_ov_darkness, 6 years ago, In English

Bangladesh Advanced Computing Society (BACS) organizes annual training camps for ICPC regional participants in different venues all across Bangladesh. For this, BACS takes an online selection contest. This year BACS decided to accommodate BdOI participants as well. To select them, an onsite contest was held simultaneously in 5 different cities. To know more about BACS, you can check their website.

Codemarshal and SSL Wireless are the sponsors of this year's contests and camps.

The contests had 8 and 7 problems respectively and were held in IOI format. We decided to merge the three give away problems into one. Adding that with the other 12 problems, we created an ICPC style set with 13 problems.

The replay contest will take place on Friday, August 10, 2018, 4 PM MSK in Codeforces Gym, and will run for 5 hours.

Problems used in this contest were prepared by Alpha_Q, aminul, codename27, flash_7, Imran_Bin_Azad, MesbahTanvir, Jami_CSEDU, kimbbakar, Tanzir5, prophet_ov_darkness, raihatneloy, s_h_shahin, SkullKnight, shovonshovo, bertho_coder, and Z0RR0.

GLHF.

UPD 1: Contest will take place on Friday, August 10, 2018, 4 PM MSK, instead of Saturday, August 11. Codeforces Round 503 (по олимпиаде ЛКШ, Div. 1) was supposed to take place on Friday, August 10 initially. The CF round has now been postponed to Saturday, August 11; and it clashes with the time we proposed earlier for this replay contest. We are shifting the contest to Friday, August 10 to avoid the clash. Sorry for notifying everyone this late.

UPD 2: Editorial has been published.

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Comments Comments (10)
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6 years ago, # |
  Vote: I like it +30 Vote: I do not like it

The contest clashes with Codeforces Round 503. Can it be held earlier, or shifted to another date?

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

Reminder: Contest starts 30 minutes later.

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

will their be any editorial??

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

How to solve problem k?

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    6 years ago, # ^ |
    ← Rev. 3   Vote: I like it +4 Vote: I do not like it

    We need a treap(with lazy propagation) to solve this task. First sort the array, and insert the numbers into a treap. Now, for updates with non-negative Y, simply do range update on treap. And for negative Y, remove those numbers (less/equal or greater/equal to X) from treap, and re-insert them after adding/subtracting with Y. At most N numbers will be removed and re-inserted in the treap for negative Y. This can be done in O((N+Q)*log(n)).

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6 years ago, # |
  Vote: I like it +15 Vote: I do not like it

Here is Editorial: http://codeforces.net/blog/entry/61127

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