Invisible Heatwave
(Published on 17. September 2020, 20:59 by Big Tiger)
Standard Sudoku Rules apply to the final numerical layout.
Both types of restraints in this puzzle indicate invisible thermometers:
Numbers Outside the Grid indicate all rows and columns containing a single largest thermometer that increases from that direction. All rows or columns where there is more than one largest thermometer are left blank. (For example, a row where one three-digit thermometer is the largest will be labeled "3"; a row with two three-digit thermometers and no larger thermometer will be left blank.)
An Arrow in the grid points to an adjacent bulb and thermometer that continue in the direction of the arrow. The digit in the cell with the arrow indicates the precise length of the thermometer, after which it breaks or reaches the border of the grid. All possible arrows are marked. (All thermometers must be 2 or greater; a 1 would result in a single cell that, by its static nature, couldn't be said to either increase or decrease.)
*****
Setter's Diary :: September 17, 2020 :: This puzzle could be called "Everything Increases 2". I was originally in no hurry to post a new puzzle, but after making the first "Increases", I couldn't stop thinking about the possibility of a version with fewer clues, and settled on the border numbers and the internal arrows. It definitely took me longer to prove to myself that it was logically solvable with a unique solution, but I am convinced. Just remember those negative constraints as you work (hint hint cough cough).
Solution code: Row 3, then Column 5
Comments
on 21. November 2020, 12:29 by _chucklehead
Hope I can help you get out of the blue zone on this one, too. People are sleeping on you; this is another amazing puzzle
*** Everyone's got their taste, lol. And I did discover over time that I found this site at the start of a major rush - probably due to half the world sitting at home with nothing to do until a virus goes away - so MOST puzzles are getting overlooked. But thank you for stopping by and glad you enjoyed it!
on 18. September 2020, 14:14 by SudokuExplorer
@BigTiger If there is a length-7 thermo in row seven (right to left), shouldn't there be an left-arrow in cell R7C7? Or have I misunderstood the rules?
*** Hello, just got home from vacation, sorry for a delay. Jesper had a similar thought in a hidden comment. It's a matter of what I thought was clear in my head VS. what other people think is clear. "The digit in the cell with the arrow indicates the length of the thermometer" was meant to inherently assume that if there was a 3 pointing in a certain direction, the FOUTH digit in that direction would have to be lower, ending the thermometer - otherwise the cell with the arrow would need to have a 4 in it instead. But at least two of you now have not necessarily understood it that way, so I will add a sentence to the rules. R7C7 does not have a left arrow because the thermometer to its left runs longer than the given digit.
*** Thanks Big Tiger for clearing my confusion. I'll give this puzzle another go :-)
on 17. September 2020, 22:46 by Greg
Good fun. There were several "Ah ha!" moments where I realised just how much information I could get out of a single clue that helped move along the solve.
*** As someone who has no idea how to pre-plan those "Aha" moments, I enjoyed finding a few myself. At least twice, there was a case of "Well, no matter where I put this thermometer, THAT cell has to be X - Cool!" Among other things. Also had a sinking feeling toward the end of my test solve that there would be an unresolved pair, but then one clue unraveled it and made it unique.
