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find all divisors 1 to 10^18

By YoyOyoYOy000y000, history, 9 years ago, In English

hi, i think all of divisors of n(1 to 10^18) with in 9 sec is quit immpossible. if any idea or solution.please share it :) thank you

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9 years ago, hide # |
 
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Iterating from 1 to sqrt(n) and using divisor pairs will give you the answer. In 9 secs, I think you can do 10^9 operations, even with the constant of the modulo operation.

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9 years ago, hide # |
 
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Good day to you,

well firstly you can start with "Pollard Rho" (you will also need something like miller-rabin), which could factorize the number in O(N^(1/4)) [it is somehow long coding with many possible mistakes, but the core is not that bad].

As you have it, you can generate all divisors by "simple recursion" in O(#NUMBER_OF_DIVISORS)

Hope I guessed rightly what you asked for ^_^

Good Luck & Have nice day!!

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    9 years ago, hide # ^ |
     
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    thanks i got it...yeah there have some mistake.. for large number it's quite impossible there is no exact solution for this ques with 9 sec :) thank you :)

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      9 years ago, hide # ^ |
       
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      Well imho there is something more exact, but this is a lesser pain ^_^

      Also the probability is "soo big" you can treat is as exact :)

      Have nice day ^_^

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