Problem 42497. Pancake sorting

Created by Jan Orwat

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>Sort a stack of pancakes by flipping them using spatula.</w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"ListParagraph\"/><w:numPr><w:numId w:val=\"1\"/></w:numPr></w:pPr><w:r><w:t>There are</w:t></w:r><w:r><w:t> </w:t></w:r><w:r><w:rPr><w:i/></w:rPr><w:t>N</w:t></w:r><w:r><w:t> pancakes with diameters</w:t></w:r><w:r><w:t> </w:t></w:r><w:r><w:rPr><w:i/></w:rPr><w:t>1:N</w:t></w:r><w:r><w:t>.</w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"ListParagraph\"/><w:numPr><w:numId w:val=\"1\"/></w:numPr></w:pPr><w:r><w:t>Spatula can be inserted anywhere in the stack and used to flip all the pancakes above.</w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"ListParagraph\"/><w:numPr><w:numId w:val=\"1\"/></w:numPr></w:pPr><w:r><w:t>Sort pancakes in increasing order.</w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"ListParagraph\"/><w:numPr><w:numId w:val=\"1\"/></w:numPr></w:pPr><w:r><w:t>Return a vector of places where spatula was inserted.</w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"ListParagraph\"/><w:numPr><w:numId w:val=\"1\"/></w:numPr></w:pPr><w:r><w:t>References:</w:t></w:r><w:r><w:t> </w:t></w:r><w:hyperlink w:docLocation=\"http://www.math.illinois.edu/~dwest/openp/pancake.html\"><w:r><w:t>math.illinois.edu</w:t></w:r></w:hyperlink><w:r><w:t>,</w:t></w:r><w:r><w:t> </w:t></w:r><w:hyperlink w:docLocation=\"https://en.wikipedia.org/wiki/Pancake_sorting\"><w:r><w:t>wikipedia</w:t></w:r></w:hyperlink><w:r><w:t>.</w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"text\"/></w:pPr><w:r><w:t>Example (horizontal view):</w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"code\"/></w:pPr><w:r><w:t><![CDATA[Initial stack:  6 4 2 5 3 1,         (\",\" indicates position of spatula)\nfirst flip:     1 3 5,2 4 6\nsecond:         5 3 1 2 4,6\n...             4 2 1 3,5 6\n                3 1 2,4 5 6\n                2 1,3 4 5 6\nsorted!         1 2 3 4 5 6\n\npositions of spatula from the begining: 6 3 5 4 3 2]]></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

170 Solutions
34 Solvers

Last Solution submitted on May 26, 2023

Last 200 Solutions

Problem Comments

1 Comment

1 Comment

David Verrelli on 12 Oct 2017

The flipping sequence does not need to be the most efficient, it just needs to (eventually) have the desired effect.

Solution Comments

Show comments

Problem Recent Solvers34

Problem Tags

Community Treasure Hunt

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

Start Hunting!

Problem 42497. Pancake sorting

Solution Stats

Last 200 Solutions

Problem Comments

Solution Comments

Problem Recent Solvers34

Suggested Problems

More from this Author40

Problem Tags

Community Treasure Hunt

Problem 42497. Pancake sorting

Solution Stats

Last 200 Solutions

Problem Comments

Solution Comments

Problem Recent Solvers34

Suggested Problems

More from this Author40

Problem Tags

Community Treasure Hunt

Players