pokeland157's blog

Do I need to learn polynomial hash and string hashing to reach expert?
By pokeland157, history, 2 months ago, In English

Do I?

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2 months ago, # |
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As an expert, I believe that it is not necessary for you to learn hashing so that you reach expert, because only in very few problems hashing is the only way to solve, but for sure it is a useful technique to learn

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2 months ago, # |
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I've never used hash stuff on CodeForces, so no

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2 months ago, # |
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Nah. Chances you'd come across such in expert level are pretty rare, and even if so, deterministic alternative (KMP/Z) usually should also be available.

Not to mention, there are a number of other more prevalent topics you could improve on and reap the result.

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    2 months ago, # ^ |
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    What are topics can I learn then?

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      2 months ago, # ^ |
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      Solve some problems, learn how to use binary search.

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      2 months ago, # ^ |
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      I'd still advise basic binary search and some common sense to crack ad-hocs.

      Extra quirk if using C++: try to learn set/multiset. They're powerful tools for a handful of problems.

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        2 months ago, # ^ |
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        I know all that stuff, I guess the only thing I can do is solve tons of more problems.

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          2 months ago, # ^ |
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          Seems like it. Either be faster or more precise with your code logic. That should do.

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2 months ago, # |
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I dont know either of those and im expert

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2 months ago, # |
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nah you dont have to but imo its not a hard concept. I just copy the usaco guide template and treat it like a black box. Moreover it may be useful in solving some problems, like I've "cheesed" some string hash problems that wouldve been impossible to come up otherwise. Just knowing that you can compare two substrings fast and what not is always good ig.

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2 months ago, # |
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Nah.

I think I never came across a problem of rating <= 1700 whose only intended solution was hashing in cf.

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