How to compute the sum of the digits of n! (n <= 1e9) ?

Revision en1, by Lucas97, 2016-11-26 20:49:25

Hi guys, today a friend asked me about this problem. He said it was just a random problem that came to his mind. So, I don't know any OJ to submit it. Do you know any way to solve it efficienty? i.e. I know we can compute it using Java or Python, but I'm looknig for something better(Imagine you have 3s as time limit)

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en1 English Lucas97 2016-11-26 20:49:25 377 Initial revision (published)