Problem 514. Spot the rectangle (Part 2)

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]
Solve

Solution Stats

52.44% Correct | 47.56% Incorrect
Last Solution submitted on Jul 04, 2025

Problem Comments

Solution Comments

Show comments

Problem Recent Solvers112

Suggested Problems

More from this Author50

Problem Tags

17x17 matrices

Community Treasure Hunt

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

Start Hunting!