Обсуждение @ 1629. Перелёт @ Timus Online Judge

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how come? Adler3D 11 окт 2008 15:28

Вот на такой тест у меня прога выдаёт 1500 и получает WA на 6 тесте. А когда она выдавала 1631, WA было на 11 тесте 0_o. Помоему из условый ответ толжен быть 1500, а не 1631. Значит ошибка в тестах ?
3
3 10 1200
23:50 01:00
2 41 300
19:19 21:30

Re: how come? Aisenshtein Daniil 11 окт 2008 15:36

No comments

Re: how come? Anisimov Dmitry 11 окт 2008 15:37

Doesn't seem like correct test: Q_1 = 3 when only 2 times are given

Re: how come? beautiful 11 окт 2008 15:46

THE SAME TO U。。。。。I GOT WA INT TEST#6 WHEN THE ANSWER IS 1500

Re: how come? Lan[ISPU] 11 окт 2008 15:54

THE SAME TO U.I GOT WA IN TEST#6 WHEN THE ANSWER IS 1500.

Re: how come? Krayev Alexey 11 окт 2008 16:01

i got ac and all that i can say is "condition sux"
(sorry it's just imho)

Re: how come? Adler3D 11 окт 2008 16:34

Я фигею, ничего вроде не менял, a WA теперь на 9 =(

Re: how come? Adler3D 11 окт 2008 16:52

я её решил. Вот состовитель молоток, всё условия правильные и незаметные.

Hint:
см. условия на D.

Edited by author 11.10.2008 16:53

Edited by moderator 13.10.2008 00:49

Re: how come? XJTU小分队 11 окт 2008 17:01

Coule you please translate it into English?? I got WA on test6 so many times! I don't know why

Re: how come? Mace(Lviv Polytechniс NU) 11 окт 2008 17:18

Nice problem. Just try to read problem statement more carefully.

Hint:
For test
3
2 10 1200
23:50 01:00
2 41 300
19:19 21:30
Correct answer is 1631.

Re: how come? Anisimov Dmitry 11 окт 2008 18:11

Mace, when I change solution to it says "1631" on your test, my solution is rejected with WA 2.
Is there any difference between your test and test #2 from the statement?

Re: how come? Igor E. Tuphanov 11 окт 2008 20:54

I can't understand it anyway. Will try to read the statement tomorrow. Again)

Re: how come? svr 14 окт 2008 11:59

Very good problem!
Conditions actual and realistic.
Time ordering is so applicable thematic that I wanted
to solve the problem from first attempt using intuitive
mining about time matter but couldn’t.
That because I am not top coder only.

Re: how come? Smielov Valery[KNU] 11 окт 2008 21:56

. Но тут он услышал шокирующую новость — из-за метеорологических, экономических и геополитических причин С ЭТОГО момента все самолёты будут вылетать из аэропорта i на Di минут позже расписания.

Edited by author 11.10.2008 22:11

Edited by author 11.10.2008 22:11

Re: how come? Igor E. Tuphanov 12 окт 2008 07:06

"because of meteorological, economic, and geopolitical reasons, all flights would leave the ith airport Di minutes later". То есть "would leave" я должен перевести как "с этого момента будут вылетать"? Видимо, это попытка сделать задачу, сложность которой основана на том, чтобы понять, чего хотел от контестантов составитель условия, или даже угадать, чего он в условии недосказал.

Re: how come? Anisimov Dmitry (Novosibirsk STU) 12 окт 2008 16:23

До момента прибытия субъекта в аэропорт все рейсы вылетают по расписанию. Задержки начинаются ровно с момента, когда субъект прибывает в аэропорт. Субъект может сесть в самолет в момент его вылета.

Спасибо Валерию. На мой ключевой вопрос, предполагающий ответ "да" или "нет", жюри в лице сами знаете кого не ответило. Я думаю, жюри получает от этого удовольствие.

Игорь, совершенно верно. Что вы хотите от вуза, в котором на приеме у декана пирамидку катают? Радуйтесь, что у них людей не едят.

Re: how come? Vedernikoff Sergey (HSE: EconomicsForever!) 12 окт 2008 17:36

Господа, я не понимаю, в чем суть спора? Ну да, надо признать, что Вы невнимательно читали условие, потому что хоть по-русски, хоть по-английски из него явственно следует, что самолеты будут вылетать с опозданиями ПОСЛЕ ТЕКУЩЕЙ ПОЛУНОЧИ. После первого ВА на контесте я еще раз хорошо перечитал условие и прога сразу без проблем сдалась.
Так что читайте условия внимательнее.

И еще - если вы участвуете в чемпионатах на тимусе, то надо хотя бы немного с уважением относиться к людям, которые это для вас совершенно безвозмездно делают, а не отпускать глупые шутки по поводу пирамидок у декана и поедание людей. Всего доброго.

Re: how come? Anisimov Dmitry (Novosibirsk STU) 12 окт 2008 19:54

Верно, я невнимательно перечитал условие 8 раз на русском и английском языках.

Юмор как бы является частью контестов довольно давно как в фабуле, так и в изобретении особенно изощренных задач. Неплохо бы признать тоже, что юмор составителей задач также не все разделяют ("украинские газопроводы", "теплотрасса"). Про пирамиду декана не я придумал.
А этот контест проводится прежде всего для внутренних нужд УрГУ.

Спасибо.

Edited by author 12.10.2008 19:56

Edited by author 12.10.2008 19:56

Re: how come? Samsonov Alex [USU] 12 окт 2008 23:12

You know, sometimes "extremely sophisticated" problems are not invented by the problemsetters for fun. Sometimes a usual problem turns out to be sophisticated and containing a lot of gaps and features. See also problem 1484. Both of them were invented first and solved by the authors second.

Don't you think the current statement is logical? What is the reason of giving the delay in the input if you only need to add it to the departure time and take it modulo 1440?

P. S. Speak English please.

Re: how come? Chmel_Tolstiy 13 окт 2008 00:32

>Don't you think the current statement is logical? What is the reason of giving the delay in the input if you only need to add it to the departure time and take it modulo 1440?

Alex, but why in another problem we need only substruct 20*sum(ai) ?

I read problem in russian and second reading help me. But in english as I know statement was bad.

Re: how come? Anisimov Dmitry (Novosibirsk STU) 13 окт 2008 10:23

Edited by author 13.10.2008 10:27

Re: how come? Anisimov Dmitry (Novosibirsk STU) 13 окт 2008 10:26

Samsonov Alex [USU] писал(a) 12 октября 2008 23:12

The bookworm problem is an old example of intended increase of problem condition. So it makes sense to supsect this problem also. I don't understand reference to the problem 1484. It is more difficult to code algorithm that produces output 1.1(0001) instead of 1.(0001), the mistake who some have made. So I'll consider this reference spurious.

Don't you think the current statement is logical?

Does that mean the CURRENT statement is not the statement used in the contest?

What is the reason of giving the delay in the input if you only need to add it to the departure time and take it modulo 1440?

What is the reason to assign origin of delays to midnight if it only adds a single if statement to a solution?

Chmel_Tolstiy писал(a) 13 октября 2008 00:32

I read problem in russian and second reading help me. But in english as I know statement was bad.

Actually, English future-in-the-past ("would leave") is intended to serve as a key (If Russian statement was written first, reference to "этого момента" was removed). Of course, if English isn't person native language it is not easy to understand.

Even more, the statement contains "meteorological, economic, and geopolitical reasons" which is obscuring and misleading evidence. If author had written that "a bug caused software malfunction and flights would leave later" it would be much clearer. In the bookworm problem, we have to apply common sense. In this problem, we have to neglect it (the obscuring reasons list), and the only valid key is verb tense. It is worth mention in naming problems authors are not so precise with English grammar (articles are missing when they are required), which is, of course, liberate way of using English language.
Of course, we might ever come to problems requiring knowledge of assembler, nuclear physics, linguistics or even biology. I don't say if it would make contests better of worse, but that would make them different.

Re: how come? Samsonov Alex [USU] 13 окт 2008 13:35

Anisimov Dmitry (Novosibirsk STU) писал(a) 13 октября 2008 10:26

Hmm... In turn, I didn't understand the problem you are talking about :) I mentioned problem 1484 "Film Rating" which doesn't contain anything about printing rational numbers. So the reference isn't spurious actually.

Does that mean the CURRENT statement is not the statement used in the contest?

No.

What is the reason to assign origin of delays to midnight if it only adds a single if statement to a solution?

It means you wrote a good code if adding a single "if" statement" was enough. And again I should say that we didn't "assign origin of delays" for fun.

Actually, English future-in-the-past ("would leave") is intended to serve as a key (If Russian statement was written first, reference to "этого момента" was removed). Of course, if English isn't person native language it is not easy to understand.
Even more, the statement contains "meteorological, economic, and geopolitical reasons" which is obscuring and misleading evidence. If author had written that "a bug caused software malfunction and flights would leave later" it would be much clearer. In the bookworm problem, we have to apply common sense. In this problem, we have to neglect it (the obscuring reasons list), and the only valid key is verb tense. It is worth mention in naming problems authors are not so precise with English grammar (articles are missing when they are required), which is, of course, liberate way of using English language.
Of course, we might ever come to problems requiring knowledge of assembler, nuclear physics, linguistics or even biology. I don't say if it would make contests better of worse, but that would make them different.

I don't understand your jokes about nuclear physics. The problems don't require any special knowledge, just a bit of common sense, that is true. Your criticism is accepted and we will pay even more attention to English statements in future, however you mentioned yourself that a statement was correct, although probably unclear for some coders. Even if so, understanding problem statements and finding non-trivial was, is and probably will be the part of ACM ICPC contests. Try practicing on World Finals problemsets, for example.

Edited by author 13.10.2008 13:36

Edited by author 13.10.2008 13:36

Re: how come? Anisimov Dmitry (Novosibirsk STU) 13 окт 2008 18:38

Samsonov Alex [USU] писал(a) 13 октября 2008 13:35

My reference (1468) was spurious, then. Pardon.

It means you wrote a good code if adding a single "if" statement" was enough. And again I should say that we didn't "assign origin of delays" for fun.

On other hand, one could write code where adding modulo operation wouldn't been enough to accomodate for simplest delays without origin, so it is vice-versa argument.

Has background story been changed since the solution and the tests were written?

I don't understand your jokes about nuclear physics. The problems don't require any special knowledge, just a bit of common sense, that is true.

This one requires total lack of common sense, indeed. Common sense SAYS "meteorological, economic, and geopolitical reasons cannot begin in a single moment. Especially at midnight."

Your criticism is accepted and we will pay even more attention to English statements in future, however you mentioned yourself that a statement was correct, although probably unclear for some coders.

You did it well with masking key feature. Not easy to imagine what could be done further. If you had intention to make it perfectly clear, you would write something like "At airport entrace, Son-on-Sam accidentally broke some device, and that caused entire scheduling network in a kind of chaos".

Even if so, understanding problem statements and finding non-trivial was, is and probably will be the part of ACM ICPC contests. Try practicing on World Finals problemsets, for example.

Well... obscuring problem statements was, is, and will be... I cannot imagine you do it without joy at all...
Just don't be offended if someone doesn't share your joy or humour.

Re: how come? Samsonov Alex [USU] 14 окт 2008 01:46

Anisimov Dmitry (Novosibirsk STU) писал(a) 13 октября 2008 18:38

Has background story been changed since the solution and the tests were written?

No. The whole statement was written first, solutions and tests second.

You did it well with masking key feature. Not easy to imagine what could be done further. If you had intention to make it perfectly clear, you would write something like "...".

I had no intention to mask the key feature or to make it perfectly clear. I had intention to write a correct statement, which corresponds to the problem I wanted to prepare.

I cannot imagine you do it without joy at all...
Just don't be offended if someone doesn't share your joy or humour.

I am not offended by this discussion at all :) I have also solved problems with untrivial moments in statement and felt joy after receiving Accepted. Especially if I understood that my first idea of problem was wrong and everything I needed was actually written in statement, but I haven't noticed it at first glance. I do feel joy when I see other teams overcome the same difficulties and in turn feel joy after receiving their Accepted. I think that solving this kind of problems is very useful and important both in ACM competitions and in life.

Now I suggest we are close to understanding each other's point of view and should soon close this topic :)

Re: how come? Anisimov Dmitry (Novosibirsk STU) 14 окт 2008 11:43

Which statement was written first, Russian or English?

Samsonov Alex [USU] писал(a) 14 октября 2008 01:46

I had no intention to mask the key feature or to make it perfectly clear. I had intention to write a correct statement, which corresponds to the problem I wanted to prepare.

There are weird names occuring in both statements, which suggests that you were also doing something at same time, with intention or no. You could take common names. Because the contest was held very well, the first assumption to any thing is that was intended.

I do feel joy when I see other teams overcome the same difficulties and in turn feel joy after receiving their Accepted.

Seemingly contradicts what have you written before about correctness of the problem was only intention.

I think that solving this kind of problems is very useful and important both in ACM competitions and in life.

There is a point of view that frauds are useful because they keep people's awareness at higher level. I wouldn't state such thing which has more to do with ethics.
In any case, acm.timus.ru, unlike many online contesters, has many problems were sarcasm is outside common scope.

Re: how come? penartur 13 окт 2008 23:35

> Your criticism is accepted and we will pay even more attention to English statements in future
You should not, the statement is clear, and anyone should be able to understand the current version as it was meant by you.
He is just mad about this because he hadn't realized that point later.

> although probably unclear for some coders
ACM is not for coders. ACM is for versatile people, who can read, understand, solve problems... and, last of all - who can code their solutions.
If this resource was intended for the coders, the problem discussed would have been formulated like "given are some numbers **description_of_numbers**, you should do **description_of_manipulations_with_these_numbers** and print a result".

Re: how come? Anisimov Dmitry (Novosibirsk STU) 14 окт 2008 00:41

Who is mad? You throw insults at me. This is inappropriate.
According to my original understanding of the problem, flights were delayed before the point Son-of-Sam arrived to the 1st airport, just he was unable to learn it before. Many contestansts have done similar mistake. In fact, both interpretations (wrong and correct) have only remote resemblance to real world.

>ACM is not for coders
Today is not the insults day.

Re: how come? Anisimov Dmitry (Novosibirsk STU) 14 окт 2008 00:59

Samsonov Alex [USU] писал(a) 13 октября 2008 13:35

The only my post here that was intended to contain a joke is where dean's pyramid was mentioned. The reference to nuclear physics etc. was to meant to say this problem requires uncommon skill. Of course most of top contestants have well developed common sense as well as various uncommon senses. Probably lawyers have similar skill, so if we find group where that skill would be common, the group would have only remote connection to ACM ICPC.

Re: how come? penartur 13 окт 2008 23:24

> "because of meteorological, economic, and geopolitical reasons, all flights would leave the ith airport Di minutes later".
> То есть "would leave" я должен перевести как "с этого момента будут вылетать"?

Посмотрите на это, как на обычную ситуацию из жизни.
В расписании есть некоторое количество рейсов - допустим, по рейсу каждый час (0:00, 1:00, ..., 23:00).
Вдруг в полночь объявляют, что по различным причинам все рейсы будут отложены на десять часов. Тот рейс, который должен был вылететь в полночь - вылетит в 10:00; который должен был вылететь в 1:00 - вылетит в 11:00 и так далее.
И как вы хотели бы это перевести, если вам не нравится нынешний вариант? Как вы себе это представляете? Что делать с рейсом, который вылетел в 23:00 - приказывать ему возвращаться для того, чтобы он смог вылететь в 9:00? А рейс, который вылетел в 15:00 и уже давно успешно приземлился в аэропорте назначения?
В условии, конечно, есть подлянка; но никаких недосказанностей нет, всё предельно корректно.

Обсуждение задачи 1629. Перелёт