Triangle Inequality
(Published on 7. December 2025, 08:00 by Kaktuslav)
Rules: Normal sudoku rules apply.
Triangles: Three digits connected by a triangle represent the side lengths of a valid triangle (i.e., the sum of any two sides is greater than the third). No two triangles in the grid have the same sum of their three digits. Every blue triangle has a greater sum than every orange triangle.
Solution code: Row 5
Comments
on 15. March 2026, 04:05 by skuntsel
Very nice construction! Easy with the blue triangles when you get the implications, but very resisting with the yellow ones. Absolutely amazing how it all comes together, let alone how to come up with such an idea.
on 19. February 2026, 10:20 by guirigui
Loved it! Very tough and required me several visits, but it slowly showed itself with very elegant steps
on 9. January 2026, 12:11 by koXx
Fantastic! Hard, but absolutely fantastic, and the rather low rating doesn’t do justice to this little gem!
on 10. December 2025, 15:43 by Krisonium
Missed opportunity to say no two triangles have the same perimeter XD. Splendid & amazing puzzle despite me doing too much arithmetic at the start before seeing the geometry of the triangle.
on 8. December 2025, 14:04 by mihel111
Once again, Santa dropped a box too early under our trees. This is more than an advent treet. What a big forgiving heart Santa has, also passing through troll villages.
on 8. December 2025, 00:05 by Tinnifer
This is normally a bit above my difficulty level but I made my way through in the end and I'm glad I did! Spectacular puzzle with some really cool and original logic.
on 7. December 2025, 20:58 by cybers
Very fun with plenty of moments that made me feel very big-brained. Helpful to have solved with pen and paper handy; curious how I would've fared without that.
