#3 Is it solvable? code error

[Nicolas Jager]

There are times when it will say it "This game is NOT solvable" when in fact it is. If one continues to play the right moves, it will then later change from "NOT solvable" back to solvable." However, this means that it's claim that it was "NOT solvable" was false.

[dannys9]

Hello Nicolas,

this is a known issue. The AI knows only one way to solve the game. If this path is blocked, it will show "not solvable", ignoring any other path. In fact, almost always there are several possibilities.

It would be impossible to test every combination. Well, not really "impossible" but too much time consuming. Usually, there are much more paths that lead to impasses than paths that lead to a solution. On each failure, the test has to be restarted. It runs everytime tiles are removed and several times when the game field is created. I fear you would notice a slower game start and a delay before you can click on the next tiles.

But enough technical stuff. I will see what I can do about it ;-)

Thanks for your report
Danny

[Anonymous]

I am playing game 18x8 with slide option on, push tiles together off and gravity off. But this statement is probably valid regardless to the options.

I performed a test on 1,000 random boards and concluded that almost 96 % of the boards were solvable.

I used a special random technique for quick evaluation of the board solvability which could be used in your program for reassessing solvability while playing. The evaluation takes less that 1 second on average.

If you are interested, please contact me at phcapron@noos.fr.

On the other hand, I found a few unsolvable boards when the option allow unsolvable games is off. The present technique could also provide some improvement.

Philippe CAPRON, from Bougival near Paris, France.

[Anonymous]

I've noticed games where it takes undoing two choices to get back to solvable just after becoming unsolvable. Why isn't one undo enough?