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simonlindholm's blog

By simonlindholm, history, 3 years ago, In English

Last weekend the finals of Swedish Coding Cup took place. Results. Congrats to _h_ for winning!

The problems are available on Open Kattis; I think they are quite nice.

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14 months ago, # |
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It looks like the reference solution to Ligatures uses SIMD. If possible, how would one solve it without SIMD?

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    13 months ago, # ^ |
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    I'm embarrassed to admit that the intended solution is the quadratic time bitset one, and I don't know of any subquadratic one. It should be possible to do it with regular 64-bit numbers at most 4x slower than the 0,37 s AVX2-based one on the Kattis leaderboard, which should pass, though you might have to do a fair bit of constant factor optimization.

    (I think it's an interesting exercise though precisely how to apply bitsets here, IMO it's far from obvious.)

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    13 months ago, # ^ |
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    How to see reference solution ?

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      4 weeks ago, # ^ |
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      quite late, but it's here: https://github.com/Kodsport/swedish-coding-cup-finals-2021/blob/main/ligatures/submissions/accepted/sl_simd.cpp

      Also, linking some resources Simon mentioned when I asked him about SIMD, in case they're helpful:

      From Simon: