Problem 595. Reduce - Map-Reduce

Created by Muthu Annamalai

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>Write reduce function, that takes arguments and constantly folds results into next call argument, finally returning a value; i.e. for a binary operator Fb,</w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"code\"/></w:pPr><w:r><w:t><![CDATA[     reduce(Fb,{a,b,c},start_val) = F(F(F(start_val,a),b),c)]]></w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"text\"/></w:pPr><w:r><w:t>Same can be done for a n-ary operators.</w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"text\"/></w:pPr><w:r><w:t>Eg. reduce(@strcat,{'foo','bar','baz','bat'},' ') = reduce(@plus,{1,2,3,4},0) = 10 reduce(@max,{1,2,3,4},{5,6,7,8},5) = 8</w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"text\"/></w:pPr><w:r><w:t>Remember, we use cell arrays for passing arguments, not matrices!</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

63 Solutions
17 Solvers

Last Solution submitted on Feb 28, 2023

Last 200 Solutions

Problem Comments

3 Comments

3 Comments

@bmtran (Bryant Tran) on 17 Apr 2012

could you separate your asserts into multiple cells so you can see which test case is failing?

@bmtran (Bryant Tran) on 17 Apr 2012

also, how do you define the n-ary behavior since max only takes up to 2 non-empty arguments?

Muthu Annamalai on 17 Apr 2012

I mean, n-ary operators are also supported, but I use max as a binary op.

Solution Comments

Show comments

Problem Recent Solvers17

Problem Tags

Community Treasure Hunt

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

Start Hunting!

Problem 595. Reduce - Map-Reduce

Solution Stats

Last 200 Solutions

Problem Comments

Solution Comments

Problem Recent Solvers17

Suggested Problems

More from this Author10

Problem Tags

Community Treasure Hunt

Problem 595. Reduce - Map-Reduce

Solution Stats

Last 200 Solutions

Problem Comments

Solution Comments

Problem Recent Solvers17

Suggested Problems

More from this Author10

Problem Tags

Community Treasure Hunt

Players

WeChat