Problem 44384. Find the nearest prime number

Created by Matthew Eicholtz

Solve Later

{"relationships":[{"relationshipType":"http://schemas.mathworks.com/matlab/code/2013/relationships/document","targetMode":"","relationshipId":"rId1","target":"/matlab/document.xml"},{"relationshipType":"http://schemas.mathworks.com/matlab/code/2013/relationships/output","targetMode":"","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\"?>\n<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>Happy 5th birthday, Cody! Since 5 is a prime number, let's have some fun looking for other prime numbers.</w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"text\"/></w:pPr><w:r><w:t>Given a positive integer x, find the nearest prime number. Keep in mind that the nearest prime may be less than x.</w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"text\"/></w:pPr><w:r><w:rPr><w:b/></w:rPr><w:t>Examples</w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"code\"/></w:pPr><w:r><w:t><![CDATA[nearestprime(5) = 5\nnearestprime(36) = 37\nnearestprime(200) = 199]]></w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"text\"/></w:pPr><w:r><w:t>NOTE: You may ignore cases in which two prime numbers are equally close to x. (e.g., x=12 --&gt; 11 and 13 are both primes).</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

2173 Solutions
570 Solvers

Last Solution submitted on Jun 12, 2021

Last 200 Solutions

Problem Comments

1 Comment

1 Comment

Tran Hiep Dinh on 21 Mar 2019

Test case No. 5
x = 911;
y_correct = 911;

Should the nearest prime number for 911 have been 907?

Solution Comments

Solution 2127687

1 Comment

1 Comment

Mehedi Hasan on 13 Feb 2020

how i can solve
which is wrong

Solution 1397315

1 Comment

1 Comment

Francis Naldo on 29 Dec 2017

Look. It's Size 80

Solution 1317338

1 Comment

1 Comment

Igor Gaponov on 21 Dec 2017

I feel for you, typing in those endless arrays of prime numbers.
You have probably figured it out by now, but instead of typing in manually the vectors prim0 and prim1 and then checking memberships, you can just run the function 'isprime(x)' which will save you lots of space and time

Problem Recent Solvers570

Problem Tags

cody5 prime numbers

Community Treasure Hunt

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

Start Hunting!

Problem 44384. Find the nearest prime number

Solution Stats

Last 200 Solutions

Problem Comments

Solution Comments

Problem Recent Solvers570

Suggested Problems

More from this Author44

Problem Tags

Community Treasure Hunt

Problem 44384. Find the nearest prime number

Solution Stats

Last 200 Solutions

Problem Comments

Solution Comments

Problem Recent Solvers570

Suggested Problems

More from this Author44

Problem Tags

Community Treasure Hunt

Players