Problem 2671. Check if vertices form a rectangle

Created by Matthew Eicholtz

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Given a set of 4 vertices defined by vectors X and Y, return true if the vertices form a rectangle and false otherwise.

X and Y are not necessarily in sorted order, but you may assume that X(i) is paired with Y(i).

Also, if computing distances in your solution (e.g. with pdist), it is recommended that you round to three decimal places.

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Last Solution submitted on Jun 29, 2018

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Jon on 17 Nov 2014

Most current solutions will fail if the four points fall on a circle but don't form a rectangle. Try adding X=[0 sqrt(2)/2 sqrt(2)/2 0]', Y=[1 sqrt(2)/2 -sqrt(2)/2 -1]'

Matthew Eicholtz on 21 Nov 2014

Jon, I updated the test suite to include parallelograms that are not rectangles. While it does not include the specific example you gave, I think it takes care of the problem. Let me know if you think there is still an issue.

Jan Orwat on 21 Nov 2014

Matt, Jon's example can 'kill' some approaches, that check for trapezoids. X=[-1 -0.5 0.5 1]; Y=[0 sqrt(3)/2 sqrt(3)/2 0]; can eliminate those solutions which check only for 3 unique distances between points. It would be beneficial, to try some trapezoids, as well as kites or rhombi. Anyway, great problem!

Matthew Eicholtz on 22 Nov 2014

Ah yes, I agree. Test suite updated again.

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Solution 531692

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James on 21 Nov 2014

Time to work on plan B; pdist isn't valid in Cody. :-(

Solution 531205

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2 Comments

Jan Orwat on 20 Nov 2014

This one should not pass, it checks for parallelograms.

Matthew Eicholtz on 21 Nov 2014

Thanks for bringing this to my attention Jan. Test suite has been updated.

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Problem 2671. Check if vertices form a rectangle

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Last 200 Solutions

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Problem 2671. Check if vertices form a rectangle

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