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Comment by ancientsofmumu | Hacker News Reader

> For instance, their Minesweeper guarantees that it is solvable - you will never have a 50/50 choice you cannot identify.

Alas, I've backed myself into a corner a couple of times and triggered "just gotta guess" choices in it - while it's generally good at this, it's not a 100% implementation based on my playing.

I find "Net" way more fun though for quick casual gaming, a 7x11 grid (depends on exact screen size) with wraparound enabled is a favorite for easy to tap but enough squares to make it take some time to solve (about 5 minutes per game, give or take).

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> Alas, I've backed myself into a corner a couple of times and triggered "just gotta guess" choices in it - while it's generally good at this, it's not a 100% implementation based on my playing.

This should not happen because the current implementation [1] always tries to solve a randomly generated puzzle deductively, and never generates a puzzle that hasn't passed the check. (There are some shortcuts, including dynamically "perturbing" the current puzzle to make it uniquely solvable.) "Solvable" puzzles do not guarantee no backtracking though, so that's probably where you gave up. Also note that you should take account for the number of remaining mines, which can frequently be the sole information left for the very last mines.

[1] https://git.tartarus.org/?p=simon/puzzles.git;a=blob;f=mines...

I think you may have overlooked a logical solve. I dug into the code for his Minesweeper at one point and IIRC it works by generating random boards and putting them through a deterministic backtracking solver that gives up when faced with one of these choices. I think it then has a way of changing the board to be solvable. Or it just generates a new one, I don't remember.

I've also played it quite a bit and can't remember having any undecidable boards.

> backed myself into a corner a couple of times and triggered "just gotta guess" choices

At least for me sometimes a situation that looked like "just gotta guess" was actually solvable by knowing the total number of remaining mines, as one choice in the "guess" would imply more mines than the other.

Once I had a field where the last place to uncover was completely surrounded by mines, revealing the digit 8 underneath.

Isn't it known how many mines are on the board, so that is not actually a problem since you could count that all of the exposed/marked mines == total # of mines?

Sorry, it was meant as an example for that, not as a counterpoint. I did solve the field without guessing, so it wasn't a problem.

Sure it's not something you're overlooking? Haven't encountered it myself.

Sometimes in constraint puzzles, one clue is also that there is a unique solution. So if doing one choice implies that some other choice can be arbitrary, that's not the solution.

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