Logic Masters Deutschland e.V.

After a long struggle, here it goes...


The following puzzle is the main version of the sloop+deconstruction concept that I actually published in the smaller version a long while ago. As some might've already guessed, this one has a lot bigger size with also much more consistent difficulty throughout compared to the previous one.

For the last few months, I'd gone through a lot of reconsiderations and made a lot of uneasy decisions on this project - including whether to keep this particular idea or not, followed by scrapping a lot of different parts and also resetting from certain point of the setting/solving; but eventually few days ago, I got to pick certain types of idea that could finally help me through a few very sticky points and then lead to a great conclusion for this project.
(this also came with some slight modifications in the original rule set as well)

In retrospective, even though this one feels more challenging in terms of difficulty, I think it also showcases a much stronger application of this entire rule set, especially the region number concept.


This is quite certainly my longest project in this year so far, and special thanks to fellow solver mellowrobinson for actually being the only tester for me and providing some insightful feedback at the end! I hope this will turn out just as well to everyone else too :)


Rules:

- Located within the grid are nine orthogonally connected regions that contain digits 1-9 once each so that digits don't repeat in any row or column of the entire grid. Any two regions cannot touch orthogonally but may touch diagonally, and other cells outside these nine regions don't contain digit at all.

- The 'region number N' of a region is defined as digit N in the top-left cell of that region, i.e. the left most cell in the top most row (in this case, top most is prioritized over left most). Each digit from 1 to 9 must occupy a region number once.

- Draw a single loop, which goes orthogonally and doesn't branch or intersect itself, that must go through all of the non-digit cells AND ALSO must visit each region once at ONLY the respective region number cell, which follows in the increasing order before back to 1 again (i.e. 1 -> 2 -> ... -> 9 -> 1).
Whenever the loop goes through a region number cell, it must make a 90 degrees turn at that cell.

- Every cell with black arrow[s] in it belongs to a region and contains digit that's equal to the combined amount of cell borders that the loop goes through in the indicated direction[s], including the borders of arrow cells as well if available.

- Every given gray cell doesn't contain digit or loop segment at all. In addition, for any given gray cell containing red arrows, digits mustn't repeat along the combined directions of its arrows.

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Similar to previous version, here's an example of how the rules work (including the extra gray cell rule). It's not an actual puzzle, but rather acts as an illustration for how the main concept works.

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Puzzle:   Penpa plus  -  Sudokupad



The answer check in penpa link will activate once all of the digits are correctly filled and also the loop is correctly drawn. For now, good luck and have fun solving!