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How to know the difficulty of questions in contest without reading them?

How are people able to identify which question is of cakewalk category and solve them so quickly in short contests? Around 100 submissions in first 10 minutes. Surely that's not enough time to read each question and then decide. I know after a while you can understand the difficulty of a problem by looking at the number of submissions later on. But which problem do you start with when there are no submissions at all?

asked 26 Apr '17, 01:43

abdullah768's gravatar image

6★abdullah768
1.9k217
accept rate: 17%


Usually i see that first two problems are easiest (but setters may change order to confuse people).

As you said, after 5-10 minutes, the accuracy % reveals everything, but assuming you are the first guy, I recommend reading the first 2 questions and going for the one you know.

Moreover, I think a "killer-instinct" can be developed by repeated participation. I personally always start with first, except when I feel that "okay, this isn't THAT easy", in case of which I go for second problem.

Make sure you know a variety of topics. A problem may be cakewalk, but if you don't know the concept, it will give you tough time!

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answered 26 Apr '17, 02:05

vijju123's gravatar image

5★vijju123 ♦
14.4k11653
accept rate: 18%

Let me share what I do to skim cakewalk questions to get solutions to them AC
1. I read all the question at least once and try to find the easiest one
2. I constantly update the contest page in a different tab whether someone is submitting solution to some problem or not, if submission passes beyond 50, I'm sure it must be cakewalk then I read the problem statement again and start solving it, For example in April cook off I solved the first problem at 154 position (13:00 min after start) by tracking the number of submission
3. Once I have submitted solution to first problem, by then Easy problem submission begins and if number of submission in second problem is too less then it must be medium problem.
4. Python favors a lot to get AC within first few minutes, In April cook off @mathecodician stood 91 by making submission using python at 7:00 and 22:00 minutes since the contest started

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answered 26 Apr '17, 02:02

neilit1992's gravatar image

3★neilit1992
1.1k13
accept rate: 20%

". I read all the question at least once and try to find the easiest one"

True. That's the only 100% accurate way to find so. But if we are ready to take some risk, I think the easy Q is among the first 2 (mostly). What do you say?

(26 Apr '17, 02:08) vijju123 ♦5★

I skim through all of them and check submission simultaneously(diff tabs). This time the first 2 weren't easiest, the ordering comes in action when submission starts. In April cook up, first question I skimmed through XORSUMS(it was at top initially if i remember correctly), then SHOPNTRIP, then I saw everyone is submitting solution to CANDY123, and then I started solving that.

(26 Apr '17, 02:14) neilit19923★
1

Oh! When I opened it I saw CANDY at top and that ABREPEAT at second. But yes, by then there was 1 AC of CANDY.

(26 Apr '17, 02:17) vijju123 ♦5★

If I go on to read everything, it would take at least 10 minutes. How are people able to submit solutions within 5 minutes? The only one who could read everything that fast would be Jhumroo from Shaka Laka Boom Boom lol.

(26 Apr '17, 11:31) abdullah7686★
1

There is some luck factor involved too. Sometimes the first question you pick turns out to be easiest. Nevertheless, participate in contests and keep an eye out for any pattern you may observe. Also, some pro-coder said "Every Q is cakewalk if you know what to do." (:p)

(26 Apr '17, 11:37) vijju123 ♦5★
1

@abdullah768 just skim through it, to get a gist and relate with some problem you have done before, don't go through minute details in the beginning. And yes sometimes its luck you'll be skimming the easiest one for the first time.

(26 Apr '17, 11:51) neilit19923★
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answered 26 Apr '17, 13:41

marshal_roxx's gravatar image

3★marshal_roxx
(suspended)
accept rate: 2%

I guess that solving Cakewalk fast is a mixture of Luck, Language Domain (i.e. I speak Spanish), fast coding, and experience to know what is the main idea of some problem barely reading specific areas of statement... this could be well trained constantly competing and some contestants have proven that they can be impressive in this sense (you ask yourself in what time it read and codified the problem to have it solved in three minutes, when are even finished to read the problem).

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answered 26 Apr '17, 03:32

ymondelo20's gravatar image

4★ymondelo20
2857
accept rate: 5%

How does Language Domain help in this, mate?

(26 Apr '17, 11:32) abdullah7686★
1

I think he is trying to refer to fact that solutions in python etc. are shorter than the same solutions in c++ or JAVA etc. Meaning, the code is shorter and crisper and hence, you can w rite it faster and submit faster.

(26 Apr '17, 11:38) vijju123 ♦5★
1

@vijju123 this is important too, well know the programming language which you use... but in fact I´m talking about common language, just to be clear take into account that not all users have to know perfectly English, Mandarin, Vietnamese or Russian (e.g. countries of Latin-America, and those who speak French).

(26 Apr '17, 15:10) ymondelo204★

Ohk! I see your point. Thanks for clarification :)

(26 Apr '17, 16:16) vijju123 ♦5★

There's basically no way to tell the difficulty of a problem without reading it, you simply can't guess anything. I sometimes try the problem with small sample input-output data or shorter problem statement, and you'll laugh sometimes I scroll down and see who's the author of the problem, ;) i.e. if it's from @kingofnumbers most probably it's easy-medium problem and I prepare myself for dynamic programming.

If the tags are provided it's easier to guess the difficulty level of the problem but tags are only provided in practice section.

At the end study the problem statement thoroughly and try to visualize that problem and find a set possible solutions.

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answered 26 Apr '17, 17:30

only4's gravatar image

4★only4
1.5k210
accept rate: 17%

edited 26 Apr '17, 17:33

Usually, when there are a lot of contestant, after some minutes you only have to follows the numbers... the amount of AC solutions will tell you which is the cakewalk and at least which could be the second and third problem to try.

Another fact is to know who is solving firstly some task... the rating of the users can give you some information about the problems. If one problem is solved at first 5 minutes by some unusual amount of low-stars users then probably it´s the cakewalk... don´t assume that first problem solved is always the easiest, because sometimes a valid strategy is to solve simple-medium-hard problems first in order to code it firstly and reduce probability of penalization due the common stress at starting (this is more used by those who expect to finish high ranked and knows they can solve almost/all problems).

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answered 26 Apr '17, 03:28

ymondelo20's gravatar image

4★ymondelo20
2857
accept rate: 5%

Reading question is a must but most people follow the technique used by @neilit1992...even I do follow this idea.
By doing this we assure ourself solving a problem that is cakewalk and looking for rest of the problems.

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answered 26 Apr '17, 16:03

adhish_kapoor's gravatar image

3★adhish_kapoor
9048
accept rate: 9%

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question asked: 26 Apr '17, 01:43

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last updated: 26 Apr '17, 17:43