- When checking the order the first time, elements above are preferred marked as wrong.
- When the user corrects his solution, the newest inserted elements are preferred marked as wrong.
This affects only cases, where there are multiple options for the same number of correct elements.
In general, the algorithm minimizes the number of elements it needs to mark as wrong.
Closes#5
When null is given, there is no card to assign
There is currently no placeholder for the missing space.
This means, if a row has no card at some column it must also have no card
at any later column.
