Problem 512. Spot the rectangle
This problem is related to the 17x17 challenge. 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.
Examples:
Input a = [ 1 0 0 0 0
0 0 0 1 0
0 0 0 0 1
0 0 0 0 1
0 0 1 0 0 ]
Output tf is false
You can't form any rectangles here.
Input a = [ 1 0 1 0
0 0 1 0
1 0 1 0
0 0 1 1 ]
Output tf is true
There is a rectangle: a([1 3],[1 3]) is [1 1; 1 1]
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1 older comment
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.
Christian Schröder
on 28 Sep 2022
Could you add
a = ones(3) - eye(3)
to the test suite?
Abdelrahman Adel
on 7 Apr 2024 at 12:36
It was a good problem.
If anyone find it's difficult , you can download my answer
http://up-4.net/d/tt5L
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