Is this board solvable?

Anything to do with minesweeper...
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wildtiger
Posts: 9
Joined: Fri Feb 27, 2015 6:51 pm

Is this board solvable?

Post by wildtiger »

Recently I've been playing a Guess Free Minesweeper for Android. The "guess free" part means that you should never have to guess to solve a board.

I came across a board which didn't seem to be solvable (i.e. required me to guess). I just wanted to share it with the community to ask whether I missed anything because according to the description of the app, all boards should be solvable (and are normally).

I've been playing custom board sizes because expert is relatively easy in guess-free mode. This board is a 30x25 board with 250 mines.

Here are the two unsolved areas of the board, with only 5 mines remaining to flag:

http://i.imgur.com/Sh901qo.png

http://i.imgur.com/h2SwoSY.png

All other flagged mines are correct, as I found out after guessing a couple of times and finishing the board.

Is this board solvable without guessing?

If not, I will report this as a bug to the app developer.

PS: I couldn't post the actual images, only links to them, as I get error "It was not possible to determine the dimensions of the image."
thefinerminer
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Re: Is this board solvable?

Post by thefinerminer »

I have uploaded a picture showing there are 5 possible solutions, and so the board cannot be solved. You need to guess, but some guesses are more likely than others.

To save space, Solutions 3/4/5 are the same except pick a different green square each time.
(Check your board, if you forgot to place 1 flag, then there are only 4 mines left and this can be solved easily).
Attachments
Possible solutions
Possible solutions
NoSolution.jpg (528.19 KiB) Viewed 8168 times
Zlix
Posts: 38
Joined: Fri Jun 13, 2014 12:29 pm

Re: Is this board solvable?

Post by Zlix »

I don't see any problem with this board. I've marked first 3 steps on image that can be done, after that you can solve upper right corner(you will get a number on step 2 that will solve that part).
Depending whether you have 0 or 1 remaining mines, you can solve upper left corner.
http://www.dodaj.rs/f/s/pR/3WbkD7CF/h2swosy1.png
wildtiger
Posts: 9
Joined: Fri Feb 27, 2015 6:51 pm

Re: Is this board solvable?

Post by wildtiger »

Zlix wrote:I don't see any problem with this board. I've marked first 3 steps on image that can be done, after that you can solve upper right corner(you will get a number on step 2 that will solve that part).
Depending whether you have 0 or 1 remaining mines, you can solve upper left corner.
http://www.dodaj.rs/f/s/pR/3WbkD7CF/h2swosy1.png
Your clicks are correct...here is the final solution (which I got only by "guessing", or so I thought):

http://i.imgur.com/d4cbhIi.png

http://i.imgur.com/zIJFG1C.png

But I don't understand how you got to those clicks? How did you work out that the one you marked "1" is a mine? Why are the other solutions posted by finerminer invalid?

Your help would be greatly appreciated and would make me a better Minesweeper!!
Zlix
Posts: 38
Joined: Fri Jun 13, 2014 12:29 pm

Re: Is this board solvable?

Post by Zlix »

http://www.dodaj.rs/f/1W/8/2qqsQSqj/h2swosy2.jpg
Hopefully that will help you. If you have additional questions, feel free to ask.
thefinerminer is quite inactive lately so he probably overlooked that board can be solved without guessing.
wildtiger
Posts: 9
Joined: Fri Feb 27, 2015 6:51 pm

Re: Is this board solvable?

Post by wildtiger »

Zlix wrote:http://www.dodaj.rs/f/1W/8/2qqsQSqj/h2swosy2.jpg
Hopefully that will help you. If you have additional questions, feel free to ask.
thefinerminer is quite inactive lately so he probably overlooked that board can be solved without guessing.
Wow, thank you so much! That seems so obvious to me now!! I don't know how I missed it. :oops:
thefinerminer
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Re: Is this board solvable?

Post by thefinerminer »

I feel realy stupid now! You can tell I have only played a few hours this year...

The solution is really easy, the 2 touches 3 squares, you know there is only 1 mine in the top 2 squares, so the 3rd is obviously a mine.

It is funny the solution is what I would guess every time, because my unconscious minesweeper brain after 15 years is better than my conscious brain. :oops:
Attachments
Solved.jpg
Solved.jpg (60.16 KiB) Viewed 8156 times
wildtiger
Posts: 9
Joined: Fri Feb 27, 2015 6:51 pm

Re: Is this board solvable?

Post by wildtiger »

http://www.minesweepergame.com/forum/downl ... php?id=401

Okay, can anyone help me with this one? I literally looked at it for over an hour and then guessed! The bottom half of the board (30x30 board with 270 mines, nominally "guess-free") and all currently flagged mines are all correct. What have I missed?

PS: I made the image by sticking 4 images together, but they were all taken in the same "state" with 17 mines remaining...
Attachments
puzzle-2015-03-09.png
puzzle-2015-03-09.png (491.95 KiB) Viewed 8155 times
Zlix
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Joined: Fri Jun 13, 2014 12:29 pm

Re: Is this board solvable?

Post by Zlix »

wildtiger
Posts: 9
Joined: Fri Feb 27, 2015 6:51 pm

Re: Is this board solvable?

Post by wildtiger »

Got it. You considered the 3 and some groups of three and two squares, each of which has "at most 1" mine in them, right? It's quite clever. I didn't spot it. Thanks a lot.
Zlix
Posts: 38
Joined: Fri Jun 13, 2014 12:29 pm

Re: Is this board solvable?

Post by Zlix »

Yes. You got it right. :)
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