Thread - stuck in this sudoku

Posts: 1801

Country : India

prasanna16391 posted @ 2012-10-23 1:02 AM

Firstly the Classic - I remember this one. What I did while solving was focus in the first box. By process of elimination, you get that R2C1, R2C3 can only contain either of 4-6-9. You've already marked R2C7 containing 4-6. This makes a triplet and eliminates 6 from the 2-6 in R2C5, so you have a 2 there. Should be ok after that.

For the variants - You can look at past Monthly tests for some. I think I remember off the top of my head an Anti Knight in Sudoclones and a Queen Sudoku in Diagonal Vision. Apart from that, you have Disjoint groups in the Fed Sudoku site itself, in the Alternatives section. So too Quadro I think. There's also this site(Where disjoint groups is called Offset, Symmetric Unequal is I think No Mirror).

Edited by prasanna16391 2012-10-23 1:05 AM

@ 2012-10-23 2:00 AM (#8788 - in reply to #8786) (#8788) Top

Posts: 337

Country : Switzerland

Fred76 posted @ 2012-10-23 2:00 AM

kishy72 - 2012-10-22 9:20 PM

and if possible post a link where i can see these versions guys
Untouchable sudoku,Disjoint groups ,Symetric unequal , Antiknight
Queens ,Quadro ,Touchy , DuoDoku.... not even heard of some of these variants...planning to take part in sudoku cup want to try atleast one of each of these versions(hopefully) before the test.

You can also find some of them in the monthly test authored by Jan Mrozowski 2 years ago, called "Classic Look-Alikes", it's basically the same concept as the 1st round of sudokucup:

http://logicmastersindia.com/lmitests/?test=M201007S

Fred

@ 2012-10-23 6:55 PM (#8796 - in reply to #8788) (#8796) Top

Posts: 419

Country : India

kishy72 posted @ 2012-10-23 6:55 PM

Thnks prasanna and Fred for the links ...did not spot the 469 combination in R2C1 ......and by the way took this Queens sudoku from Diagonal vision....valued at 85 points i assumed initially that is too much for a simple sudoku (atleast it appeared to me like that with so many numbers) But i soon realised that this sudoku is worth its weight in gold......tried at 3 different times today to give my mind a break and still could not proceed beyond this point.....i could not use the queen constraint at all with just 1 9 locked till this point.

@ 2012-10-23 6:57 PM (#8797 - in reply to #8796) (#8797) Top

Posts: 419

Country : India

kishy72 posted @ 2012-10-23 6:57 PM

kishy72 - 2012-10-23 6:55 PM

just to make sure everyone knows the rules of queen sudoku....in simple words 9 is assumed to be a chess queen ...no queen(9) can attack other queens(other 9s)...all other sudoku rules apply

Edited by kishy72 2012-10-23 7:12 PM

@ 2012-10-23 7:02 PM (#8798 - in reply to #8797) (#8798) Top

Posts: 419

Country : India

kishy72 posted @ 2012-10-23 7:02 PM

and in symmetric unequal what does cells 180deg symmetric to each other mean..????totally blank....could not make out head or tail out of it...kindly explain guys..

@ 2012-10-23 7:22 PM (#8799 - in reply to #8797) (#8799) Top

Posts: 337

Country : Switzerland

Fred76 posted @ 2012-10-23 7:22 PM

The queen sudoku of diagonal vision's instructions booklet is a bit too hard... It's my fault.
We discussed about it there: http://logicmastersindia.com/forum/forums/thread-view.asp?tid=451&s...

Fred

@ 2012-10-23 7:25 PM (#8800 - in reply to #8798) (#8800) Top

Posts: 337

Country : Switzerland

Fred76 posted @ 2012-10-23 7:25 PM

kishy72 - 2012-10-23 7:02 PM

and in symmetric unequal what does cells 180deg symmetric to each other mean..????totally blank....could not make out head or tail out of it...kindly explain guys..

R1C1 is symmetric to R9C9, R1C2 is symmetric to R9C8, R2C1 symmetric to R8C9, etc... does it help?

Fred

@ 2012-10-23 7:37 PM (#8802 - in reply to #8799) (#8802) Top

Posts: 419

Country : India

kishy72 posted @ 2012-10-23 7:37 PM

Fred76 - 2012-10-23 7:22 PM

The queen sudoku of diagonal vision's instructions booklet is a bit too hard... It's my fault.
We discussed about it there: http://logicmastersindia.com/forum/forums/thread-view.asp?tid=451&s...

Fred

So i am not the only one stuck it seems! But Beautiful theme nevertheless....similar to what u do in a chess game.......think ahead and see if it is advisable to go with that continuation...perhaps thats why this sudoku is rightly named queen sudoku....i was looking for a logical continuation....did not look for a contradiction at all....

@ 2012-10-23 7:45 PM (#8803 - in reply to #8800) (#8803) Top

Posts: 419

Country : India

kishy72 posted @ 2012-10-23 7:45 PM

Fred76 - 2012-10-23 7:25 PM

kishy72 - 2012-10-23 7:02 PM

and in symmetric unequal what does cells 180deg symmetric to each other mean..????totally blank....could not make out head or tail out of it...kindly explain guys..

R1C1 is symmetric to R9C9, R1C2 is symmetric to R9C8, R2C1 symmetric to R8C9, etc... does it help?

Fred

So going by the same logic R5C1 is symmetric to R5C9 ,R5C2 is symmetric to R5C8 etc...and the only cell symmetric to itself in the entire grid is R5C5...?!

@ 2012-10-23 8:05 PM (#8804 - in reply to #8803) (#8804) Top

debmohanty

Country : India

debmohanty posted @ 2012-10-23 8:05 PM

kishy72 - 2012-10-23 7:45 PM
So going by the same logic R5C1 is symmetric to R5C9 ,R5C2 is symmetric to R5C8 etc...and the only cell symmetric to itself in the entire grid is R5C5...?!

That is correct. Now all the additional rule says is "If two different cells are 180⁰ symmetric to each other, they must contain different digits".
More examples: mock12 IB & PB - http://logicmastersindia.com/lmitests/?test=mock12

@ 2012-10-29 11:00 PM (#8843 - in reply to #8804) (#8843) Top

Posts: 419

Country : India

kishy72 posted @ 2012-10-29 11:00 PM

not able to touch the solution in this untouchable sudoku....cells with same digits dont touch diagonally..first sudoku of this variant which i had tried ...where am i missing the trick here?

Edited by kishy72 2012-10-29 11:01 PM

@ 2012-10-30 4:32 AM (#8846 - in reply to #8843) (#8846) Top

Posts: 337

Country : Switzerland

Fred76 posted @ 2012-10-30 4:32 AM

kishy72 - 2012-10-29 11:00 PM

not able to touch the solution in this untouchable sudoku....cells with same digits dont touch diagonally..first sudoku of this variant which i had tried ...where am i missing the trick here?

Kishy: BE CAREFUL NOT TO POST THE SUDOKUS OF A COMPETITION BEFORE IT IS FINISHED !

The competition is now finished, but it was not the case when you posted this one.

That being said, try to place the 2 in row 5, and then you can place lot of other digits

Fred

@ 2012-10-30 8:48 AM (#8850 - in reply to #8846) (#8850) Top

Administrator

Country : India

Administrator posted @ 2012-10-30 8:48 AM

Fred76 - 2012-10-30 4:32 AM

Kishy: BE CAREFUL NOT TO POST THE SUDOKUS OF A COMPETITION BEFORE IT IS FINISHED !

The competition is now finished, but it was not the case when you posted this one.

Kishy72, Consider this as your first and last warning. Never post puzzles from LMI / other sites while the competition is running. Always wait for few hours after the competition ends.

@ 2012-10-30 10:24 AM (#8852 - in reply to #8846) (#8852) Top

Posts: 419

Country : India

kishy72 posted @ 2012-10-30 10:24 AM

Fred76 - 2012-10-30 4:32 AM

Fred

BE CAREFUL NOT TO POST THE SUDOKUS OF A COMPETITION BEFORE IT IS FINISHED

This thought did cross to me immediately after i had posted it but i left it at that thinking that the person had just as much a chance of going wrong as getting it correct by seeing this sudoku but anyway i know that that is not the point.It wont occur again.

@ 2012-10-30 10:33 AM (#8853 - in reply to #8850) (#8853) Top

Posts: 419

Country : India

kishy72 posted @ 2012-10-30 10:33 AM

Administrator - 2012-10-30 8:48 AM

Fred76 - 2012-10-30 4:32 AM

Kishy: BE CAREFUL NOT TO POST THE SUDOKUS OF A COMPETITION BEFORE IT IS FINISHED !

The competition is now finished, but it was not the case when you posted this one.

Kishy72, Consider this as your first and last warning. Never post puzzles from LMI / other sites while the competition is running. Always wait for few hours after the competition ends.

You could have removed my post instead of admonishing me like this or you could have said to me in private before u posted this.This looks like slapping me in the face and saying 'Dont post sudokus in this forum'.I m not a fugitive under warrant

@ 2012-10-30 11:55 AM (#8855 - in reply to #8853) (#8855) Top

Posts: 1801

Country : India

prasanna16391 posted @ 2012-10-30 11:55 AM

kishy72 - 2012-10-30 10:33 AM

You could have removed my post instead of admonishing me like this or you could have said to me in private before u posted this.This looks like slapping me in the face and saying 'Dont post sudokus in this forum'.I m not a fugitive under warrant

Well you'll have to be to solve the next test :P Anyway, in all seriousness, what you are doing(posting on forum and asking doubts) is great. In fact we've been encouraging beginners to do that for some time now. Its just that, when something like this happens, we need to make sure it doesn't happen again through anyone, not just you. I think that was the reason for the public warning. Do be careful in the future :)

@ 2013-02-09 9:00 PM (#9814 - in reply to #8611) (#9814) Top

Posts: 13

Country : Germany

purzelbaumfan posted @ 2013-02-09 9:00 PM

I just wanted to say a quick Thank You for the tricks I've learned only on these 2 pages. I have never looked for triplets in a puzzle! This is the next way to go! Thank you very much!

@ 2013-03-29 4:54 PM (#10467 - in reply to #8611) (#10467) Top

Posts: 13

Country : Germany

purzelbaumfan posted @ 2013-03-29 4:54 PM

http://i46.tinypic.com/14yba10.jpg

I have had trouble seeing a way to solve this puzzle completely avoiding trial and error. Can someone please help me?

@ 2013-03-29 4:55 PM (#10468 - in reply to #8611) (#10468) Top

Posts: 13

Country : Germany

purzelbaumfan posted @ 2013-03-29 4:55 PM

I tried to fit it rigth into the post, but it was rather big.

Edited by purzelbaumfan 2013-03-29 4:59 PM

@ 2013-03-29 11:33 PM (#10470 - in reply to #8611) (#10470) Top

Posts: 1801

Country : India

prasanna16391 posted @ 2013-03-29 11:33 PM

I can proceed further by seeing that 5 in Row 7 put in either place puts 7 in R7C4, which can be seen using row 4 for one placement of 5, and the other is pretty straightforward. There's another sticking point in proving that R9C2 can't be 4 (4-5 in the 7th box means 5 must be in R4C2, where'll 7 go in C2?). Its pretty difficult, but thats the closest I can come to a solid path.

@ 2013-03-30 3:39 PM (#10473 - in reply to #8611) (#10473) Top

Posts: 13

Country : Germany

purzelbaumfan posted @ 2013-03-30 3:39 PM

Thank you very much. That was a very decent solving path without trying too much. I appreciate your help.

@ 2013-03-30 10:04 PM (#10476 - in reply to #8611) (#10476) Top

Posts: 13

Country : Germany

purzelbaumfan posted @ 2013-03-30 10:04 PM

This is another puzzle I didn't get any further with. Any suggestions?

Edited by purzelbaumfan 2013-03-30 10:08 PM

@ 2013-03-31 9:51 AM (#10477 - in reply to #8611) (#10477) Top

Posts: 1801

Country : India

prasanna16391 posted @ 2013-03-31 9:51 AM

There's a way to eliminate 4 from R5C6 (It then goes in R7C5 and eliminates both possibilities in column 8!). Also, only 4/8 can be in R9C9 because of R7C5, which means one of 4/8 in Row 7 is in C8/9, so R7C6 is 3/9 only. After that, I could prove that R9C4 cannot be a 3 by just using 3s and 9s and seeing the crowd-out that happens in R1C9. But this last step's bordering on guessing, so I'm not sure if thats the intended path.

@ 2013-04-03 11:33 PM (#10511 - in reply to #8611) (#10511) Top