MinMax-Sudoku with 21 clues
(Published on 28. April 2020, 23:30 by Rawcoder)
This is one of my first, self-made, Sudokus. I am thankful for any tips. I am happy to post my other Sudokus here.
Rules:
Classic Sudoku rules apply. Additionally, a number outside the grid indicates the sum of lowest and highest digit of the corresponding first three adjacent cells.
Solution code: Row 3 followed by row 4
Comments
on 29. April 2020, 23:53 by Rawcoder
Added a clue to solve the Sudoku properly now. Thanks to everyone for helping me find my mistake.
Hope the puzzle is now more enjoyable.
on 29. April 2020, 23:11 by Rawcoder
Thank you so much for your advice. I will keep that in mind. Still new to creating puzzles. I will add a clue that will resolve everything without a problem and change the bitmap for the puzzle.
At least now I know where my mistake was. Thanks again. I will recheck all my other puzzles to see if there is something similar.
Hope you like my other puzzles better than this one.
on 29. April 2020, 22:51 by Ours brun
@Rawcoder Also, one thing to keep in mind: using uniqueness arguments on variants is often very risky, as they can conflict with the additional constraints. If you use a UR or a BUG on a cell that could have been resolved using one of the variant's constraints, you may very well end with a wrong digit.
on 29. April 2020, 22:44 by Ours brun
@Rawcoder As I mentioned in an earlier (hidden) comment, when you reach a point where you only have two 9 clues left, there is nothing more to do. At this point, it is indeed tempting to use a uniqueness argument, which does lead to a valid solution; but it is not the only solution. This is why you should never use a uniqueness argument when testing a puzzle - only do so when you already have confirmation that the solution is indeed unique.
on 29. April 2020, 22:39 by Realshaggy
Hidden Unique Rectangles and BUG are both uniqueness arguments. If you used that, that's the source of the mistake for sure. You should avoid these techniques when creating puzzles.
on 29. April 2020, 22:35 by Rawcoder
@Puzzle_Maestro I used Hidden Unique Rectangles to get rid of a number and then the BUG. After that, one of the MinMax-Clues solved the last bit that would otherwise lead to two solutions. I guess that this is my mistake then.
Can I contact you on the forum? I would really like to explain at what point I used the logic mentioned above.
on 29. April 2020, 22:26 by Puzzle_Maestro
@Rawcoder: have you used a uniqueness argument in your logic? Because uniqueness arguments rely on the existence of a unique solution, so you cannot use them to prove that a puzzle is unique (as you don't yet know that there is a single solution).
on 29. April 2020, 22:21 by Rawcoder
@Realshaggy Don't get me wrong. I'm a by no means an expert solver and here are some really really good solvers. I just don't see where my logic is wrong. Could we discuss this in the Forum? I would appreciate your help.
on 29. April 2020, 21:35 by Realshaggy
When all hints are used, everything that's left is basic sudoku logic. Nothing complicated. If multiple people tell you, that there is still more than one solution left at that point, you should consider that you are maybe wrong. I think everybody who solved it (including me) just tried all possible solution codes (there are like 4).
It's a pity, since I've actually enjoyed it very much. It's not a brand new bizarre ruleset, but a somewhat known variant that is not a Killer or a Sandwich.
on 29. April 2020, 21:26 by Rawcoder
I am very sorry. I definitely had an error in my solution code. I just solved the puzzle again and I just get one solution. Nevertheless, that's no excuse for the mistake with the solution code. But I have to say that there is a bit of a complicated logic involved in the final part. If it's needed I can give the last part of logic I used to solve it, but I think I will add one more clue so the last part gets solved by that clue. I will give the puzzle two more days and I will check on the comments.
Thank you so much for your comments.
on 29. April 2020, 21:22 by Rawcoder
Error in the solution Code.
on 29. April 2020, 17:54 by zorant
Puzzle has more solutions!
on 29. April 2020, 16:47 by Realshaggy
Yes, still broken.
on 29. April 2020, 11:50 by ManuH
Multiple Solutions?
on 29. April 2020, 07:56 by Rawcoder
I corrected the title. Thank you.
I solved the puzzle a couple of times and always found just one solution. I also double checked the solution code.
Thank you for your comments.
on 29. April 2020, 07:52 by Rawcoder
Originally had "19" clues in the title but there are 20 clues.
on 29. April 2020, 03:47 by Imperial Marcher
I've found a solution but it's not being accepted. Are there multiple outcomes?
on 29. April 2020, 00:48 by sf2l
I have found 3 solutions but none of the is accepted. Is this because of the 20th clue? Is there a mistake in the title which mentions 19 clues while there are 20? Does the 20th have something special.?
