No Same Sums
Divide the grid into regions of any sizes and any shapes, so that no number appears more than once within a region. Regions that have at least one common number cannot touch each other, not even diagonally. When you add up all numbers in a region, the resulting sums must be different for all regions.
(Rules and example from WPC 2019 IB)
History of the puzzle
Appeared on WPC 2019/Round 12, an "innovations" round. The puzzles were written by Silke Berendes.
Appearances in the past WPCs
- WPC 2019/Round 12 by Silke Berendes