Is the Solitaire minigame 100% solve-able?

[ragnakore]

or not?

[furrykef]

If the deck is completely randomized, then no. It would be easy to create unsolvable states. How likely they are, I have no idea.

[uNiels 💗]

As it's a game with perfect information, one could very well write a program that tries to solve a given initial state via backtracking (i.e. which can take back moves). Then you can hand-feed deals to it that Shenzhen I/O presents to you and if you encounter one that the program (provided it works correctly) can't solve, you know that the answer is "no".

[Inari]

I'm fairly sure there are many layouts you just can't solve

[G4mm4g0bl1n]

Solitaire initiats with a constant amount of cards and a Random Number Generator for mixing.
The Second step is a sorting Algorythm which creates the Card field.
Solitaire is a small "Math" Game, because its aimed to the Question "Is the given Situation (Equation) solvable when rules (Stack Rules for Solitaire) counts?

Equals to the NPN Problem in Information Technologies.
https://en.wikipedia.org/wiki/NP_%28complexity%29

So Solitaire has to be sometimes impossible to solve. The best Solitaire Gamers can recognize in an early game phase if they can solve or not solve the game.

[uNiels 💗]

Well, it may be impossible to solve if you shuffle the cards truly randomly (and even that depends on the particular type of game), but not if the algorithm generating the initial state is designed so that it only generates solvable games. And that's what I'm wondering about - is the initial deal generated truly randomly or with only solvable games in mind.

[G4mm4g0bl1n]

When the typically Solitaire algorythm is used then its random like it has to be.
Mahjong also aims to this system.

[uNiels 💗]

But we don't know what algorithm is used. That's exactly why we're wondering.

If with Mahjong you mean Mahjongg solitaire games (where you need to remove tiles stacked similar to a pyramid) a.k.a. Shanghai solitaire a.k.a. Taipei, then no, the "typical" (for me, according to the ones I played) Mahjongg solitaire algorithm always generates solvable games in the sense that if you were able to see all tiles (even the hidden ones) you could always solve it in case you perform the correct moves.

It's not hard to come up with such an algorithm. You start with a cleared board and then you randomly select valid reverse moves and fill up the board step by step. If you hit a state where there is no valid reverse move and the board is not yet filled up, you recursively backtrack and select different moves. You do that until the board is completely filled up, which is then the initial state for the human player.

An analogous algorithm would work for this Shenzhen solitaire card game.

[G4mm4g0bl1n]

I know, but thats not what Solitaire is aimed for. As I told you. Solitaire is a game about "Guessing its solvable or not". The Game itself proofs if its or its not. A good Solitaire Gamer starts to recognize in a few steps if it is possible or its not. Whats the factors about if the Gamefield is possible to solve or not when the deck shuffle is absolutly random? Thats the Question behind Solitaire and not solveable by machines at the moment without touching a card.

[Neko_Baron]

sometimes I think I cant solve it but I realise I can work the cards around because of there being 3 colours and can manage a win, but sometimes I know I need to reset the cards.

[uNiels 💗]

Solitaire games are not about guessing if they are solvable or not. On the contrary, it's really frustrating if you get stuck and you don't know if it is because of a wrong move you made or because you had an initial position that wasn't solvable to begin with.

That's why in my opinion a solitaire game on the computer should strive to present only solvable games to the human player. After all playing solitaire is about honing your strategy and logical thinking and thus making the right moves that lead you to the solution (as opposed to the wrong moves that get you stuck). At least for me. And that's why I prefer solvable games to begin with where I know exactly that when I get stuck it's my own fault and not the computer's.

And that's exactly what the question of the OP is about.

[Moe]

Well I got it on my 3rd try and I felt like it's such an elegant and scientific game. Did they invent this version of solitaire? Damn I love this game. Zachtronics <3

[uNiels 💗]

Originally posted by 24.2 percent:

Well I got it on my 3rd try and I felt like it's such an elegant and scientific game. Did they invent this version of solitaire? Damn I love this game. Zachtronics <3

The in-game description seems to suggest that they invented this particular variant / set of rules, however, I don't know. It's the same class of solitaire as Microsoft Freecell, but it obviously has some important differences.

I especially like that there are 3 colors / suits instead of 4, which makes it harder to accidentally land yourself in a dead end due to the color / suit (on the tableau at the bottom).

[Richard]

I did it in 3 or 4 tries, which suggests a low % are unsolvable (though admittedly, this is anecdotal)

[ragnakore]

Personally I only like 100% solvable puzzles. Otherwise what is the use of trying to kill oneself for something impossible?
This is why I like Rubik;s cube, spider solitaire and the like. The regular solitaire? NO!

If this mini solitaire game isnt completely solvable, then not a fan of it.

[CyberShadow]

Originally posted by blubberdiblub:

As it's a game with perfect information, one could very well write a program that tries to solve a given initial state via backtracking (i.e. which can take back moves). Then you can hand-feed deals to it that Shenzhen I/O presents to you and if you encounter one that the program (provided it works correctly) can't solve, you know that the answer is "no".

Hey, I've done just that:
https://www.youtube.com/watch?v=ul1y4ubNR1A

So far, I haven't encountered a layout my bot couldn't solve. If you think you ran into an unsolvable deck, you could send me a screenshot of the original state (how it was dealt, before any of your moves), and I'll check if a solution exists.