Each number outside the diagram represents one group of connected fields within the loop in this row/column, in correct order. Each number is equal to the edges of the fields of its group which are used by the loop. Different groups must have at least one field outside the loop between them.
All numbers 2, 3, 5 and 8 are given. The other numbers are, if single-digit, given with a '?'; and if double-digit, given with a '??' - a single-digit number (e.g. 6) cannot be written as '??'.
Solution code: The sizes of all areas outside the loop - clockwise and beginning at the top left corner.
on 13. April 2024, 08:52 by Nick Smirnov
Penpa+:
https://tinyurl.com/24l5zgpf
on 7. July 2016, 19:04 by Uhu
English description added.