Resolving since poster already solved the kata, so they probably know the answer :)

I am glad you enjoyed it! You are aware though that your solution sometimes fails for some small boards?

With backtracking, you won't get too close to max required size.

It depends what exactly you mean by "[... algorithm you mentioned]", but if it is what I think it is, then it's worth a shot. Still, things depend on details of approach and details of implementation. Some algorithms pass test suite in ~5s, and some are on the edge of timing out.

this might help you https://en.wikipedia.org/wiki/Methods_of_computing_square_roots

Maybe your solution has problems with input {1} ? The answer should be {2}

Hi,
You are right. If input eq {1,1,1}, the answer will be {1,1,2}.
Could you please re-test your solution? We already have 43+ correct c++ solutions and looks like all tests are correct.