Double Dutch Sudoku Advent (3) - Thermometers vs. Edge Sums
(Published on 3. December 2014, 12:00 by Richard)
Eisbär (Arvid) and I have created a fresh sudoku advent calendar in which we combine a well known variant with a relatively unknown variant every day. Combining variants leads to interesting and surprising new solving techniques.
Logically solvable
All puzzles can be solved completely logically although the logic is sometimes well hidden and is inherent to the combination of restrictions that the different types offer. For that reason we have written some solving hints for most of the puzzles, published in a very tiny font. If you want to read the hints, simply copy these in a text editor and enlarge the font size.
Thermometers
Place the digits from 1 to 9 in each row, column and 3x3-block. The digits in each thermometer-shaped region should be in increasing order, from the bulb to the end.
Edge Sums
Digits outside the grid are the sum of the first and the last digit in that row or column.
Solving hints
R1C1, R9C1, R9C9 = 1 or 2; R1C9 = 6 or 7
1 in C9 in R9C9; R9C1 = 2; R1C1 = 1; R1C9 = 7
Maximum for R1C5 and R9C5 = 7; Edge sum 13 in C5 = {6,7}; R1C5 = 6; R9C5 = 7
R9C6 and R1C4 = 8; R9C7 and R1C3 = 9
R1C2 = 5, R9C2 = 6
Rows 1 and 9 can be completed
R5C5 = 8
Long diagonal thermometers:
R6C7 = 1/3; R5C6 = 2/4; R4C5 = 3/4/5; R3C4 = 5/7; R2C3 = 6/7/8
R4C3 = 1/2; R5C4 = 2/3; R6C5 = 3/4/5; R7C6 = 5/6; R8C7 = 6/7/8
R6C7 not 3 since it would block all possibilities for R6C5; R6C7 = 1
1 in middle block in R4C4
1 in R5C2
R4C3 = 2; R5C4 = 3; R5C6 = 2; R46C5 = pair {45}
9 in R5 in R5C8; 9 in R4C6; 9 in R6C2
R6C46 = pair {67}
7 in R4 locked in R4C78; 7 in R5 in R5C1
R5C9 = 4; R6C1 = 8; R7C1 = 9; R7C9 = 2
Solution code: Row 2, followed by column 7
Comments
on 28. March 2022, 15:02 by Nick Smirnov
F-puzzles:
https://f-puzzles.com/?id=y85bgevp
CTC App:
https://tinyurl.com/4f8xf3k2
on 20. December 2014, 16:06 by uko50
War für mich bisher das schwerste Rätsel.
Aber toll, alles logisch auflösbar
on 4. December 2014, 12:31 by Richard
Fixed minor typo in solving hints. Thanks Rollo!
on 4. December 2014, 12:27 by Rollo
Ich finde die Hinweise auch klasse und versuche es so wie flaemmchen, sonst hätte ich auch den kleinen Fehler nicht bemerkt. Danke für diese wundervollen Adverntsgeschenke!
on 4. December 2014, 11:25 by flaemmchen
Ich finde das mit den Lösungshinweisen gut. Ich gucke nebenher, ob ich den gleichen Weg gehe - nicht immer genauso, aber fast ;-))
Bei diesem hatte ich eine Schlussfolgerung nicht verstanden und mit der Alternativ-Ziffer weitergemacht ... das ging aber sofort schief!
on 4. December 2014, 07:57 by Richard
@berni, SilBer and others: One of our main goals with the calendar is that players learn new solving steps. And I am not talking about all kinds of sudoku steps like forcing chains, Jelly fishes and other exotic moves. The steps we want to learn to players are intrinsic logic to the variant(s). For that reason we hope that players read the provided hints. During solving or afterwards, we don’t mind. In this puzzle there is a nice move that is inherent to Thermometers. It is general applicable, so if you know how it works, you can have have advantage of it during the rest of your puzzle career!
So, to all players: please read the hints if you want to! Consider them as Christmas gifts. :-)
on 3. December 2014, 22:42 by ibag
@berni und SilBer: Ging mir ähnlich, ich hab sie alle getestet ... und es lohnt sich, durchzuhalten. Die werden einfach immer besser. Und ich bin ja eigentlich auch kein Sudokufreund. Am Ende hab ich aber geschrieben, dass mir das Testen großen Spaß gemacht hat.
on 3. December 2014, 22:27 by SilBer
Puh! Also wenn der Schwierigkeitsgrad kontinuierlich ansteigt, dann bin ich ab morgen raus. ;)
Oh, na sowas, Berni hatte ja fast das Gleiche geschrieben... Ist das ein gutes oder ein schlechtes Zeichen??
on 3. December 2014, 21:51 by berni
Hab' mich zwischendurch verrannt und schon fast die Lust verloren - Sudoku sind einfach nicht meins - aber im zweiten Anlauf hat's doch noch geklappt... Keine Ahnung, wieviele Tage ich noch durchhalten werde...
on 3. December 2014, 13:56 by Richard
@Fred: you can read it yourself in the provided hints. :-)
on 3. December 2014, 13:53 by Fred76
Only 2 stars (=easy puzzle)?
I found it quite hard, perhaps I missed something in the solving path...
