Wayoutfinisher's blog

Main concepts in Div. 2 problems
By Wayoutfinisher, 10 years ago, In English

Hey everyone,

I want to know what concepts (ex**.implementation, sorting, greedy etc**.) do Div. 2 contests emphasize on. I need to know so I can improve on these areas so I can do better in future Div. 2 contests.

Thank you.

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10 years ago, # |
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I think you can look at problemset and find out which types of problems usually exist in div2 contests. But as you said it is often implementation, greedy, maths, constructive, brute force, strings, sometimes graphs.

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10 years ago, # |
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Sometimes dp

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10 years ago, # |
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In my opinion in C,D,E you can expect a lot of stuff since it already overlaps with Div1. But for strictly Div2 problems — A,B, they usually emphasize on coming up with some simple but clever idea or being able to quickly implement an annoying algorithm. They usually don't require a lot of coding and often don't have some well-known algorithm in them, hence the "implementation,sorting,greedy" tags.

When I was starting in Codeforces at first, I found out that the best way to be better at Div2 problems is to solve Div2 problems. I see you've done only one official competition so there are still 200+ competitions waiting for you. You can virtually participate and try to get the A,B right in the time limit, or simply practice (though I prefer virtual participation).

When I first joined Codeforces I would do tons of virtual competitions and that quickly improves your skill of solving those A,B problems. Good luck :)

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    5 years ago, # ^ |
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    Thanks Enchom

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    5 years ago, # ^ |
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    If we are kind of ok with solving Div 2 (A, B) questions what algorithms would you recommend to level up now to move on to C problems and above? Should i go for dp 1 st or should i go for trees and then eventually graphs from there?

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      5 years ago, # ^ |
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      How about just solve C problems and see what's on them...

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        5 years ago, # ^ |
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        I was meaning to ask which one should we go for first

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          5 years ago, # ^ |
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          And I am meaning that is a wrong way to think about it. Do not go by topic, just look at C problems and if you can't solve look at editorial and if there is topic you don't know learn that.

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      5 years ago, # ^ |
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      Ignoring that my comment is from 5 years ago, of course if you can comfortably do A, B you move on. Always challenge yourself.

      Regarding topics, DP, trees and graphs in general are very basic so you will have to learn all eventually. There is no real benefit of prioritising one over another since you'll need them all if you want to do well.

      Finally, for beginners I'm a proponent of the approach SuperJ6 mentioned — solve problems and learn the concepts that are needed to solve them. It will make progress more natural and applications of the topics will be more obvious.

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    5 weeks ago, # ^ |
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    Hey! I am too struggling for solving div 2 question. It's question and approach is totally different from 3 and 4 div. If I am not getting the idea how to tackle div 2 what to do?? Should I prefer solution videos 2 3 then ???

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