> What kind of shuffling does your program use?

The shuffling is random, but only winnable decks are generated (by default). The computer algorithm/solver is described here: https://FreeSolitaire.win/strategy

So it’s pure chance you got an easy shuffle.

> In any regard, I like your implementation.

Thanks, I’m glad you like it! If you have suggestions for improvement, I’m all ears (here or by e-mail) ;-)