This one should be in between my two previous puzzles of this type regarding difficulty. Hope you enjoy!
Rules
Divide the grid in regions, such that no two regions of the same size touch orthogonally. Each cell contains a number that indicates the size of the polyomino it is in. Clues outside the grid indicate the sum of numbers between the unique segments of highest numbers and lowest numbers in the row or column.
Example
A dash (-) means there is no valid sandwich clue in that row/column. Note how in row 5, there is no valid clue, because even though the highest numbers in the row (the 8s) are from the same region, it is unclear which one would have to be chosen for the sandwich because they are separated. This is not a problem in for instance column 1, where all 8s in the column are connected within the column and thus form a single, unique segment of largest digits.
The puzzle
Solve on Penpa
Solution code: Row 2, Row 8
on 7. January 2022, 23:00 by marcmees
very nice. thanks.
on 1. January 2022, 13:55 by SudokuExplorer
The logic felt very approachable and easier to start, so thanks for making it! :-)
on 31. December 2021, 18:04 by MagnusJosefsson
Great puzzle, well done Mark! I think it very nicely balances the difficulty to be consistently interesting and enjoyable while never getting frustrating. Lower end four stars difficulty for me.