A better implementaion could be something like:

std::array< int,3> solveEq(std::array< std::array< int,4>,3> const& input){
}

This would be more ideomatic C++.
No need to deal with heap.
I hope I did not mess the dimensions in the parameter, but you get the idea.

I labled this as an issue, because it forces to programm non ideomatic C++.
This teaches how not to programm in C++ and does not help to get a better programmer.
It should be deleted and reworked.

I really would like to have to be able to down vote a kata.

I often see C++ katas which impose outdated and (now considered) bad style.
Mostly it looks like a java programmer offers his kata to C++, wihtout having any idea how to write proper C++.

The hidden tests make it impossible to refactor it.
One is forced to follow this bad practice to complete the kata.

The author refuses to change the kata, because it would invalidate the results of all other solvers.
I can understand this.

If the goal of this project is to help improving a programmers skill,
katas should be reviewed by people who know how to programm in the language the kata is offered.

skipped because it imposes Java style in C++.
Those katas do not help any one to get better in C++.

For the C++ Kata: I loved the task.

But disliked the programming style.
Please stop writing Java in C++.
There is no need to put this in an object, if there is no state.
The first thing I wanted to do, was to make this just a function.
But the test suite contains tests I can not change.

Could replace "s.clear()" with "return 0"