/**
* @param cards Array of cards for the game.
* @throws IllegalCardSetException If given cards are not valid
* playing cards for the concentration game,
* i.e. the array is null, some card in the array is null
* or cards do not make pairs.
*/
Blue/Dog Red/Tree Blue/Dog Red/Tree
Blue/Dog Red/Tree Blue/Dog Red/Tree
Blue/Dog null Blue/Dog null
null null null null
Testovací třída ConcentrationTest vám může pomoci odhalit
některé chyby.