Problem 42791. Number of divisors of a given number

Created by Zikobrelli

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120 Solutions
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Last Solution submitted on Jul 10, 2020

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Peng Liu on 31 Mar 2016

It would be better to add squared integer numbers n in the test suite, in which case, the number of divisors is odd. However, the test suite only contain non-squared integer n, in which case the number of divisors is always even.

James on 31 Mar 2016

Any particular reason why sqrt is forbidden?

Peng Liu on 31 Mar 2016

The divisors are symmetric about sqrt(n). I guess the intention to forbid sqrt might be to eliminate brute-force search approaches, which need to search over 1~sqrt(n).

Zikobrelli on 1 Apr 2016

Peng Liu ,thanks for the suggestion.I added a few tests.
James, the reason sqrt is forbidden is what Peng Liu suggested.

Jan Orwat on 1 Apr 2016

Hey, this problem is essentially the same as problem 2664 by Jean-Marie.

Peng Liu on 1 Apr 2016

Good catch!

Solution Comments

Solution 860807

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Atsushi Ueno on 1 Apr 2016

It is not good idea to use arrays from 1 to n.

Solution 860492

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1 Comment

bainhome on 8 Apr 2018

nice! really nice.

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Problem 42791. Number of divisors of a given number

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Problem 42791. Number of divisors of a given number

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