Noureldin's blog

[Gym Contest] ACM Egyptian Collegiate Programming Contest (ECPC 2017) online mirror
By Noureldin, history, 6 years ago, In English

Hello CodeForces! I'd like to invite you to the online mirror of the 2017 ACM egyptian collegiate programming contest ,which will be held on Wednessday, 6 July 2018, 02:00pm Cairo time

contest link: ACM ECPC 2017

standings: link

ACM ECPC 2017 Highlights:

the problems were prepared and tested by : Thrax -chief judge-,Badry, Noureldin, Jarrar, Safrout, Lvitsa, amrSamir, Amirnasr, islam-al-aarag, justHusam and RedStone

problems authors:

Assessment — islam-al-aarag

Breaking the curse — Badry

Cheering parabolas — Thrax

Dream Team — Lvitsa and Thrax

Evaluations — Noureldin

Forgot the Flag! — Noureldin

Glorious Stadium — Jarrar

Half Nice Years — Lvitsa and Thrax

Important matches — justHusam

Jacking ticket — Thrax

Katryoshka — Lvitsa

Lazy ERCD — Mohamed Fouad `

You will be given 5 hours to solve the problems.

Good Luck and have fun!

UPDATE as some of you found out the test sets weren't complete and only samples were ported to the gym version ... that's due to a mistake I made while porting the contest

what happened?

I tried importing the contest normally by coping the contest.xml to the ftp server but it generated alot of errors which I couldn't understand at the time so I imported the problems manually but forgot to run the doall.sh and as a result none of the big test files were generated

now the contest is part of 'codeforces history' so I can't modify it, so I created another one with the original tests used in the contest so have fun with ECPC17

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Comments Comments (22)
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6 years ago, # |
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Auto comment: topic has been updated by Noureldin (previous revision, new revision, compare).

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6 years ago, # |
  Vote: I like it +10 Vote: I do not like it

I think it will be on Friday.

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6 years ago, # |
  Vote: I like it +11 Vote: I do not like it

We scincerely apologize, we just found out that one of the hard problems had the wrong test file (it was a much easier file) we will fix that and rejudge its results. We will update you once this is done.

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    6 years ago, # ^ |
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    Was that problem B? I see total straight forward solution (no suffix array, data structures) has got AC. You guys should fix it asap.

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6 years ago, # |
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40030586 don't know why O(1) gave TLE :/

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    6 years ago, # ^ |
      Vote: I like it +9 Vote: I do not like it

    you should read from file this the problem you can solve it by add this line in first line of main function

    freopen("lazy.in","r",stdin);

    good luck ^_^

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6 years ago, # |
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How to solve problem G ?

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

Many of the problems do not have proper dataset. For example: B,E,F,H etc(I did not look into all the problems). They are not even close to the constraints given. I hope you will look into it.

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    6 years ago, # ^ |
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    G as well, I'm disappointed that I wasted about 45min debugging my O(log(n) * t) solution when the O(n * t) solution passes without a hitch x)

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      6 years ago, # ^ |
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      FYI, none of that stuff happened at the onsite. It appears there is some issue with the test data when the contest was uploaded to codeforces. Like stated, it will be probably fixed as soon as possible.

      My advice to you is to try and solve the problems with correct complexities, and forget about "Accepted" for now.

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

Will you publish an editorial? And please fix the test case issue. It's really disappointing to see totally naive solution get accepted with given constraints.

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

Noureldin Do you know what happened with the test data? because almost every problem only has 2 small cases, can you fix it, please????

Thanks in advance

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    6 years ago, # ^ |
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    unfortunately I forgot to run the doall.sh script so only the samples were included in the tests and now I can't modify the tests because the contest is part of 'CF history' .... but I plan to rerun the contest with the original cases soon

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

      Why don't you use import from Polygon?

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        6 years ago, # ^ |
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        for some reason it generates errors ... if you have some experince with this then can you pm me ?

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6 years ago, # |
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Auto comment: topic has been updated by Noureldin (previous revision, new revision, compare).

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6 years ago, # |
  Vote: I like it +5 Vote: I do not like it

In problem A, I keep getting WA on test 6 of the 78th case.

Judge's answer is 0.32812 and mine output is 0.32813

I tried to just output that testcase in better precision and finds out that my answer is actually 0.328125000

And I tried to print out that testcase which is actually "3 1.0 1 1 7"

After doing some calculation, I found out that the answer of this testcase should be 21/64, which is equal to 0.328125

The judge's answer is wronged, please fix it.

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    6 years ago, # ^ |
      Vote: I like it +5 Vote: I do not like it

    Noureldin Please take a look at this

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      6 years ago, # ^ |
      ← Rev. 2   Vote: I like it +13 Vote: I do not like it

      fixed ... I've rejudged one of your submissions and indeed it's correct

      PS: the problem was a rounding error, during the contest we used a different solution to generate the correct answers

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3 weeks ago, # |
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Iam getting TLE at test 4 in problem A

O(K * N^3) can't pass A?

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    3 weeks ago, # ^ |
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    I reduced it to O(K * N^2) now, but got WA at test 6 :(

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