Compute sum of divisor count function for triplets of positive integers
Difference between en4 and en5, changed 18 character(s)
Given parameters $a, b, c$; $max(a,b,c) \le 9000$. Your task is to compute $\sumSigma\limits_{x = 1}^{a} \sumSigma\limits_{y = 1}^{b} \sumSigma\limits_{z = 1}^{c} d(x*y*z) $ where $ d(n)$ is the divisor count function : the number of positive divisors of $n$.↵

This is the final problem in my recent OI Mocktest, I can only solve it to the first subtask: $max(a,b,c) \le 200$, by iterating over all triplets $(x,y,z)$ and adding $d(x*y*z)$ to the result variable, to compute $d(x*y*z)$, I used applied prime sieve.↵

Can you suggest the algorithm for the final subtask?↵

Any help would be highly appreciated!

History

 
 
 
 
Revisions
 
 
  Rev. Lang. By When Δ Comment
en7 English ace-in-the-hole 2020-11-27 13:16:50 19 Tiny change: '(x*y*z) $ where $ ' -> '(x*y*z) $ by modulo $2^30$ where $ '
en6 English ace-in-the-hole 2020-11-27 12:26:53 18 Reverted to en4
en5 English ace-in-the-hole 2020-11-27 12:25:56 18
en4 English ace-in-the-hole 2020-11-27 12:21:45 48
en3 English ace-in-the-hole 2020-11-27 12:17:34 66
en2 English ace-in-the-hole 2020-11-27 12:16:05 331 Tiny change: 'z)$, I use applied p' -> 'z)$, I used applied p' (published)
en1 English ace-in-the-hole 2020-11-27 12:12:49 236 Initial revision (saved to drafts)