Problem 594. "Look and say" sequence

Created by Alex Feinman

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>What's the next number in this sequence?</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>[0]</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>[1 0]</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>[1 1 1 0]</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>[3 1 1 0]</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>[1 3 2 1 1 0]</w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"text\"/></w:pPr><w:r><w:t>This a variant on the well-known</w:t></w:r><w:r><w:t> </w:t></w:r><w:hyperlink w:docLocation=\"http://en.wikipedia.org/wiki/Look-and-say_sequence\"><w:r><w:t>\"look and say\" or Morris sequence</w:t></w:r></w:hyperlink><w:r><w:t>, where each new iteration is made up by 'saying' the number of numbers you see. That last line is \"one 3; then two 1s; then one 0\".</w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"text\"/></w:pPr><w:r><w:t>Create a function that returns the next element of this sequence, given a vector as a starting seed..</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

467 Solutions
160 Solvers

Last Solution submitted on Jul 03, 2021

Last 200 Solutions

Problem Comments

4 Comments

4 Comments

Show 1 older comment

Tim on 17 Apr 2012

Test suite case 3 seems to be incorrect.

@bmtran (Bryant Tran) on 17 Apr 2012

yeah, test case 3 should be [1 1 2 3 1 1 1 5 2 2] by my calculation

Alex Feinman on 17 Apr 2012

Sorry about that. Cut and paste fail.

Jay Austin on 2 Sep 2020

Test case 3 is still incorrect.

Solution Comments

Solution 1788201

1 Comment

1 Comment

Thara Jose on 15 Apr 2019

I tried solving this in MATLAB & it gave correct answer for the 3rd test suite also

Problem Recent Solvers160

Problem Tags

arrays math sequences

Community Treasure Hunt

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

Start Hunting!

Problem 594. "Look and say" sequence

Solution Stats

Last 200 Solutions

Problem Comments

Solution Comments

Problem Recent Solvers160

Suggested Problems

More from this Author3

Problem Tags

Community Treasure Hunt

Problem 594. "Look and say" sequence

Solution Stats

Last 200 Solutions

Problem Comments

Solution Comments

Problem Recent Solvers160

Suggested Problems

More from this Author3

Problem Tags

Community Treasure Hunt

Players