Problem 514. Spot the rectangle (Part 2)

Created by Ned Gulley
Appears in Matrix Patterns I

Difficulty:Rate

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This problem is related to the 17x17 challenge. See also Part 1 of this problem. Given a matrix in which each element is either 1, 2, 3, or 4, determine whether or not any rectangles are present. A rectangle is a formed whenever four instances of the same value appear in the corners of a rectangular region of the matrix.
Examples:
 Input  a = [ 4 1 2 4 1
              3 3 2 1 4
              3 2 4 1 1
              1 4 3 2 2
              1 1 1 4 4 ]
 Output tf is false
You can't form any rectangles here.
 Input a = [ 1 4 3 1
             3 1 4 1
             1 3 4 1
             1 1 2 3 ]
 Output tf is true
There is a rectangle: a([1 3],[1 4]) is [1 1; 1 1]

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Last Solution submitted on Feb 19, 2025

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1 Comment

Abdelrahman Adel on 7 Apr 2024

it was a good problem.
Here is my m File Solution : http://up-4.net/d/tt7S

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