Wjexmrc's blog

By Wjexmrc, history, 2 weeks ago, In English,

Hi I'm unable to solve the following problem spoj problem . I've tried but can't deduce anything , any hints/ideas are welcome.

 
 
 
 
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12 days ago, # |
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anyone?

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10 days ago, # |
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I can suggest you the following strightforward approach:

  • derive or find the exact formula $$$S(n) = \Large \sum\limits_{d|n} \frac{n!}{d!\,(\frac{n}{d}!)^d}$$$
  • represent large numbers as its prime factorisation; i've used
struct component
{
  short cnt[1229];
};

where 1229 is the number of prime numbers till 10000 ($$$N_{max} \times K_{max}$$$) and cnt is the power of corresponding prime number in order to transform all multiplications and divisions to additions and substractions

  • use optimised bigint library for converting factoring numbers into digital form.
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    7 days ago, # ^ |
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    Thanks for replying i finally understood how to derive the formula and got it accepted.