Problem 512. Spot the rectangle

Created by Ned Gulley

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>This problem is related to the</w:t></w:r><w:r><w:t> </w:t></w:r><w:hyperlink w:docLocation=\"http://bit-player.org/2009/the-17x17-challenge\"><w:r><w:t>17x17 challenge</w:t></w:r></w:hyperlink><w:r><w:t>. Given a matrix filled with ones and zeros, determine whether or not any rectangles are present. A rectangle is a formed whenever four ones appear in the corners of a rectangular region of the matrix.</w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"text\"/></w:pPr><w:r><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[ Input  a = [ 1 0 0 0 0\n              0 0 0 1 0\n              0 0 0 0 1\n              0 0 0 0 1\n              0 0 1 0 0 ]\n Output tf is false]]></w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"text\"/></w:pPr><w:r><w:t>You can't form any rectangles here.</w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"code\"/></w:pPr><w:r><w:t><![CDATA[ Input  a = [ 1 0 1 0\n              0 0 1 0\n              1 0 1 0\n              0 0 1 1 ]\n Output tf is true]]></w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"text\"/></w:pPr><w:r><w:t>There is a rectangle: a([1 3],[1 3]) is [1 1; 1 1]</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

263 Solutions
82 Solvers

Last Solution submitted on May 26, 2021

Last 200 Solutions

Problem Comments

2 Comments

2 Comments

rifat on 15 Jun 2014

test cases imply that the question title should be "spot the square"

Ned Gulley on 14 Jan 2015

I added a rectangular (non-square) test case. Thanks for the note.

Solution Comments

Solution 63821

2 Comments

2 Comments

Ned Gulley on 21 Mar 2012

This is a good answer. I changed the test suite so that you wouldn't have to deal with logical input matrices. Sorry about that!

Ned Gulley on 20 Jan 2015

This code is referenced in the following blog post: http://blogs.mathworks.com/community/2015/01/19/robot-game-playing-in-matlab-part-2/

Problem Recent Solvers82

Problem Tags

17x17 matrices

Community Treasure Hunt

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

Start Hunting!

Problem 512. Spot the rectangle

Solution Stats

Last 200 Solutions

Problem Comments

Solution Comments

Problem Recent Solvers82

Suggested Problems

More from this Author50

Problem Tags

Community Treasure Hunt

Problem 512. Spot the rectangle

Solution Stats

Last 200 Solutions

Problem Comments

Solution Comments

Problem Recent Solvers82

Suggested Problems

More from this Author50

Problem Tags

Community Treasure Hunt

Players