Problem 42791. Number of divisors of a given number

Created by Zikobrelli

Solve Later

{"relationships":[{"relationshipType":"http://schemas.mathworks.com/matlab/code/2013/relationships/document","relationshipId":"rId1","target":"/matlab/document.xml"},{"relationshipType":"http://schemas.mathworks.com/matlab/code/2013/relationships/output","relationshipId":"rId2","target":"/matlab/output.xml"}],"parts":[{"partUri":"/matlab/document.xml","relationship":[],"contentType":"application/vnd.mathworks.matlab.code.document+xml","content":"<?xml version=\"1.0\" encoding=\"UTF-8\"?><w:document xmlns:w=\"http://schemas.openxmlformats.org/wordprocessingml/2006/main\"><w:body><w:p><w:pPr><w:pStyle w:val=\"text\"/></w:pPr><w:r><w:t>Given a Number n, return the number of his divisors without listing them</w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"text\"/><w:jc w:val=\"left\"/></w:pPr><w:r><w:t>example:</w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"text\"/><w:jc w:val=\"left\"/></w:pPr><w:r><w:t>n=14 ; Divisors={1,7,2,14} ; y=4</w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"text\"/><w:jc w:val=\"left\"/></w:pPr><w:r><w:t>n=68 ; Divisors={1,2,34,17,4,68} ; y=6</w:t></w:r></w:p></w:body></w:document>"},{"partUri":"/matlab/output.xml","contentType":"text/xml","content":"<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"no\" ?><embeddedOutputs><metaData><evaluationState>manual</evaluationState><layoutState>code</layoutState><outputStatus>ready</outputStatus></metaData><outputArray type=\"array\"/><regionArray type=\"array\"/></embeddedOutputs>"}]}

Solve

Solution Stats

152 Solutions
43 Solvers

Last Solution submitted on Oct 18, 2021

Last 200 Solutions

Problem Comments

6 Comments

6 Comments

Show 3 older comments

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

1 Comment

1 Comment

Atsushi Ueno on 1 Apr 2016

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

Solution 860492

1 Comment

1 Comment

bainhome on 8 Apr 2018

nice! really nice.

Problem Recent Solvers43

Problem Tags

divisors

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Problem 42791. Number of divisors of a given number

Solution Stats

Last 200 Solutions

Problem Comments

Solution Comments

Problem Recent Solvers43

Suggested Problems

More from this Author12

Problem Tags

Community Treasure Hunt

Problem 42791. Number of divisors of a given number

Solution Stats

Last 200 Solutions

Problem Comments

Solution Comments

Problem Recent Solvers43

Suggested Problems

More from this Author12

Problem Tags

Community Treasure Hunt

Players