kirjuri's blog

Most valuable problems list
By kirjuri, 10 years ago, In English

Hi. Today competitive programmers certainly have a lot of online resources to practice. Nevertheless, there are so many problems out there, that it's hard to find some "valuable" problem sometimes. By "valuable", I mean a problem that is not just some repeated-idea problem or some problem that the participant already encountered before, or maybe just some problem that provides no new knowledge or it's too long/boring to be worthy to practice, since you will expend more time reading/understanding/coding the problem in relation to what you really learn from it. So, I would like everyone interested to post a small (or big?) list of problems that he/she considers VERY valuable so far in his/her practice so far. If people like the idea, we can later collect this information and compile some nice list of "The Most Valuable Practice Problems" or something similar. Thanks for reading and looking forward to hear the opinion from the community!

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10 years ago, # |
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Well, I will post 5 problems that I saw in the past and that I like them very much, besides these problems provided me somehow with better insights for other problems later, at least in the sense of "opening" the creative sense:

Enigmatic Device — NEERC 2009-2010 Northern Subregional, problem E

Parking — TopCoder Single Round Match 236 Round 1 — Div I, Level 3

Long Dominoes — Andrew Stankevich Contest 10, problem E

Lanes — NEERC 2010-2011 Moscow Subregional, problem L

Policija — COCI 2007 Olympiad, 2nd problem

Hope you like them!

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    10 years ago, # ^ |
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    Thanks for interesting problems.

    Could you tell how did you solve enigmatic device(i tried to gooogle it, but i didnt find anything)?

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      10 years ago, # ^ |
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      There is an editorial for it, but it is in Russian — you may find it here. Jury archive with solutions is also there :)

      Key observation is the fact that sequence x, x^2, x^4, x^8, x^16... is periodic modulo 2010 with preperiod of length 2 and period of length 10. It allows us to write a solution with segment tree.

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10 years ago, # |
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http://www.informatik.uni-ulm.de/acm/Locals/2003/html/histogram.html

Very great problem, similiar idea found in many other problems :)

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