Active Loop
(Published on 27. October 2024, 00:24 by Andrewsarchus)
Rules:
- Normal Sudoku rules apply.
- Active Cells:
A cell is said to be "Active" or "Activated" if it can be the target cell of a valid numbered rooms clue. That is, if it is N cells from the edge of the grid, where N is the digit in the cell at that edge (at one end of its row or its column). It is possible for a cell to be activated multiple times (up to once for each of the four edges of the grid). - In this puzzle, the Active Cells form a 1-cell wide orthogonally connected loop, which does not branch and which does not touch itself, not even diagonally. All of the Active Cells are on the loop, and all of the cells on the loop are Active.
- Cells with arrows are never on the loop. The digit in an arrowed cell is the distance to the nearest loop cell in the indicated direction(s). All possible arrows are given.
- White Dots separate consecutive digits. Not all possible white dots are necessarily given.
Other Activated Cell Puzzles:
If you enjoyed this puzzle, and would like to see other puzzles which utilize constraints involving Activated Cells,
then check out some of the links below:
- Other Activated Cell puzzles by Andrewsarchus:
-
Activated Cell puzzles by RockyRoer, who as far as I know,
was the first to use the constraint, and coined the term "Activated Cells":
Play Online:
ctc: Active Loop
Solution code: Loop cells in Rows 4,5,6 in reading order, no spaces
Comments
on 19. January 2025, 00:53 by jgunter
Really enjoyed this one. It took a while to understand all of the implications of the active cell loop, but once I did the puzzle flowed quite nicely! Approachable puzzle for me (a relative newbie) with some cool logic.
on 3. December 2024, 20:47 by Jensa
Amazing!
on 19. November 2024, 04:43 by Thwip_Snikt
I gotta say it took forever to wrap my head around the rules but once I got there the solve was a lot of fun.
on 4. November 2024, 18:12 by Andrewsarchus
added links to other active cell puzzles
on 2. November 2024, 13:01 by masha
hi Im really sorry ,but I just find so many contradictions in this that Im fairly certain I must have misunderstood the rules .I'd be very grateful for anyone up to explaining the third box, centre digit to me .Since ( to me )it seems to violate the active cell requirement.
I'd be glad to help correct your misunderstanding of the rules, but please be more specific about how your interpretation of the rules leads to a contradiction.
--Andrewsarchus
on 28. October 2024, 19:12 by Andrewsarchus
added image to explain counting differences for active cell indexing vs arrows
on 28. October 2024, 18:26 by virus_dave
Very interesting and very fun puzzle. I definitely agree with Cam and Zeekfox though; the phrasing around "active cells" is ambiguous unless you already know what it means. An example or better explanation would be helpful here.
Example: A one on the edge activates itself.
example added
--Andrewsarchus
on 28. October 2024, 17:05 by Zeekfox
Like someone else said, I'd love an example on the "N cells from the edge" rule. Because a 1 on an arrow indicates the adjacent cell, but a 1 on the edge activates the cell it occupies. And that's slightly confusing at first reading of the rules.
example added
--Andrewsarchus
on 27. October 2024, 22:52 by cam
I wasn't sure how to count from the edge as to me it feels like you count differently than you do from the arrow. I reached a contradiction and had to reset the puzzle. An example might be helpful.
example added
--Andrewsarchus
Thank you so much! I've updated the rating to "very nice" :) This was an awesome puzzle!
--Cam
on 27. October 2024, 21:30 by mihel111
This was my first active cells puzzle. And it made my day.
Refreshing and c-activ-ating.
Well done ;-)
on 27. October 2024, 20:59 by Franjo
Took some time to get my head around this ruleset. Never heard of active cells before. But then I got a nice flow through the solving path. Thank you so much for creating and sharing this lovely gem.
on 27. October 2024, 19:25 by marcmees
very nice. thank you
on 27. October 2024, 16:43 by Snookerfan
Very nice! Thank you
on 27. October 2024, 12:14 by RockyRoer
Forgot how much I love active cells. Thanks for setting it!
Hard one to judge difficulty... If you're familiar with active cells, this will be easy (go for a speed run?) - but if not, it will take a little longer to discover the consequences of active cells. I've got a nice picture of Active Cells on my Activated Kropki puzzle: 000BXH
on 27. October 2024, 02:08 by wisty
Super cool! Very smooth solve path for such a daunting concept.
on 27. October 2024, 02:00 by GorgeousNicko
This was a real challenge and the logic was intriguing (oh somebody used that word already).
on 27. October 2024, 01:37 by MSDOS
Very intriguing concept! Loved the logic and the challenge!
