Jahid's blog

By Jahid, 9 years ago, In English

Hi!!! A->B->C... C->B->A...A->C->B ...C->A->B

Among these orders which order you would like to follow in Div. 2 contest for good rating? or what's your technique? Sometimes I try to follow last order but most of the times doesn't work :(

I didn't mention D and E cause they are out of my range now :p I should try to Discover D and E ... How you try?

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9 years ago, # |
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I like to solve A first cause solving it in minimum times can give me a good rank.sometimes try to solve C first but it don't fail severely.

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    9 years ago, # ^ |
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    I have tried C .. but it took so many timed that my rating has gone down ...

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9 years ago, # |
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I didn't mention D and E cause they are out of my range now :p

Secret of good rating — make them not out of your range:)

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    9 years ago, # ^ |
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    thnx Bro I_love_Tanya_Romanova ... it was a inspiration .. When you were an expert ... then what you did to go further? Can I get some guidelines to follow?

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9 years ago, # |
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I've always been a fan of the good old A-B-C-D-E. It is somewhat safe and if you learn to solve the problems fast, it's actually a quite nice order.

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    9 years ago, # ^ |
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    Bro Enchom ... usually I also follow this order .. But I can go to at best in problem C. Actually, I see some coder solve problem C first and they got good rating .. that's why I wished to know the secret ? :)

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      9 years ago, # ^ |
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      Well as I_love_Tanya_Romanova said, it's much more important to learn and improve in order to get bette rating. The order of A-B-C might give you some kind of improvement, but I don't think it will be crucially significant.

      When I first joined codeforces, I could only solve A and B in Div2. I never tried any different order than the regular one, and a few months ago I reached red :)

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        9 years ago, # ^ |
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        There's a much sacrifice and hard-work need to need to reach a destination. Mercy from GOD is also necessary. Specially in programming, it's like cricket. if you practice, u can be the king :) Wish to be a Red coder someday :)

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        9 years ago, # ^ |
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        Well you are downplaying your skill. Your first three contests you solved 3 problems in each. Either way your are inspiration to all of us who practice!

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          9 years ago, # ^ |
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          Nah, I'm not. Before doing an actual competition I did some virtual ones and practicing in which I had trouble solving C at least half of the times. I was happy when on the real competition I actually managed to do it, and I would then do like 3-4 virtual competitions (that's up to 8 hours) daily. So I improved pretty quickly.

          And thanks, I believe that everyone can become red after enough time practicing :P

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9 years ago, # |
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It depends from person to person, but then again, it is an interesting question. Perhaps we can find some patterns from statistics. I am not very good at these things, perhaps DmitriyH can help us on this. Like what is the expected position of each of the 5! order in a contest. How many users used each of the 5! orders. This could be an interesting experiment. Is there really a correlation between rating and order of solve?

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    9 years ago, # ^ |
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    forthright48 ... I also think it depends on someone's skill in solving !!! But, I think , there's an factor to decrease the points of each problem during contest . Researching them , one clue can come out :)

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9 years ago, # |
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I think it is better to first solve A and then next solve the one which is solved the most.

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9 years ago, # |
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from my humble point of view ... I tried all the variations just like you mentioned and I was disappointed almost every time because when I solve C (I mean pass the pretests) it just fails the system test .... but i can tell you this ... B --> A is much better than A --> B and then you can try C

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9 years ago, # |
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It depends at lot from person to person. Personally, when I was in Div. 2, my strategy was this: I solved very fast A and B (usually within 10-30 minutes), then I focused on C. Sometimes I solved it, sometimes I didn't (usually I didn't, at the beginning).

If I didn't solve it, I'd have an average position and my rating wouldn't be affected too much (it would increase or would decrease very little), so I'd maintain myself. If I solved it, the rating would usually increase (and sometimes I'd enter Div. 1).

Having this strategy for 2 years leaded me to my current level where, in an usual Div. 2 round, I solve A, B, C and sometimes D and/or E if I'm in a good mood.

In Div. 1 rounds, my strategy depends on score distribution and authors.

My advice is to solve the problems gradually and do upsolving after each contest. In my opinion, for Div. 2, A and B are usually very-very easy and being unable to solve them fast means that you might have big gaps. Try to fill them by practicing!

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    9 years ago, # ^ |
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    thanks for your explanatory suggestion.. I have noticed from different persons record that solving A,B,C in 1st hour of contest without (wrong submission) or (wrong submission+hack) can lead to Div 2 . But it hard to solve them within 1st hour or around 1st hour. I have solved problem C for approximately 5/6 times and when I try to do it quickly then I've got system testing failure. I think, Practicing can solve this problem.

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9 years ago, # |
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I usually do A-B-C, but sometimes B or even A is tricky...

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Today I tried the order A-B-C and Alhamdulillah could pass the system test(!!) successfully :)

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9 years ago, # |
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Which order you are planning to follow in the Good Bye Contest ? :)

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    9 years ago, # ^ |
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    After a bit thinking, I have found that, the question should be "In which order the problem can be read for optimal result" ?? Because, Suppose, I have solved problem A, B. Now its time to C and D and E . For Div 2 they are commonly algorithmic so it is possible that the algorithm for problem C is not known by me but the algo for problem D is known to me cause we learn algo one by one. So, there I can solve problem D instead of C earlier and for solving order, D comes earlier than C.

    So, I think the question should be about the order of problem reading instead of solving.

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9 years ago, # |
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In Division 1, I always try B->C->A.. I guess I would do the same ordering in Division 2...

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9 years ago, # |
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The order you solve problems in is obviously not as important as your ability to solve these problems, but for fun, let's take a look at this problem for fun.

Let's assume that problems A, B, C are worth 500, 1000, 1500 points, respectively. Let's also say you solve A, B, C in x, y, z minutes, respectively.

Note that if you solve A, B, C at times a, b, c, you will get 500 - 2a + 1000 - 4b + 1500 - 6c = 3000 - 2a - 4b - 6c points.

If you follow the order A -> B -> C, they will be solved at times x, x + y, x + y + z, so your points value will be 3000 - 2x - 4(x + y) - 6(x + y + z) = 3000 - 12x - 10y - 6z

If you follow the order C -  > B -  > A, we will have A, B, C solved at times x + y + z, y + z, z, so your points value will be 3000 - 2(x + y + z) - 4(y + z) - 6z = 3000 - 2x - 6y - 12z

A -> C -> B will give points equal to 3000 - 12x - 4y - 10z

C -> A -> B will give points equal to 3000 - 6x - 4y - 12z

You can use this code to calculate which strategy is most optimal.

For example, when (x, y, z) = (5, 10, 20), A -> B -> C is the most optimal way to go.

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    9 years ago, # ^ |
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    In general, it is a well-known problem — you have to sort problems by time[i]/penalty[i], if you want to get highest score.

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      9 years ago, # ^ |
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      Maybe we can write problem about it:

      Input: First line has 5 integers, each describing number of points each problem is worth. Second line has 5 integers, number of submissions he will take until he gets the problem right. Third line has 5 integers, time it will take to solve each problem.

      Output: Maximum possible score

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I go with CBA style. You should know Div2C is Div1A, most of time it can be solved in ten minutes by Div1 coders, you shouldn't be afraid of it!

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9 years ago, # |
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Well I usually look at the problems first. I usually do A first but if I see B/C is easy I'll do them first. If there're any other "obvious/approachable" problem I will do them first, even if it's E (but this occurs rarely). Not all Ds and Es are hard, sometimes you just need to think a bit ;) Overall, I recommend A -> B -> C unless you're very confident about solving B/C quickly.