Problem 780. Give a matrix that matches itself when rotated

Given n and s, return a n-by-n matrix a of integers such that

 sum(sum(a == rot90(a))) 

is equal to exactly s. The integers should be chosen from the set 1 to n.

So for instance, if n is 2, and s is 2, you could return

 a = [ 1 1 
       2 2 ] 

since rot90(a) matches a in exactly one place.

For any n and s, a is of course not unique. I'm only checking to make sure the conditions are true.

Solution Stats

65.52% Correct | 34.48% Incorrect
Last solution submitted on Dec 26, 2018

Problem Comments

Solution Comments

Problem Recent Solvers11

Suggested Problems

More from this Author63

Problem Tags