please help me find some ur if any. I do not want to guess

Post the puzzle or solving technique that's causing you trouble and someone will help

please help me find some ur if any. I do not want to guess

Postby tommy » Fri Jun 09, 2006 5:05 pm

Code: Select all
[code]     
+---+---+---+     
|-68|-52|-7-|     
|---|6-9|-5-|     
|---|--3|2-6|     
+---+---+---+     
|4-6|---|389|     
|859|346|127|     
|73-|---|564|     
+---+---+---+     
|-73|---|---|     
|-8-|237|---|     
|-9-|86-|73-|     
+---+---+---+     
[/code]     
tommy
 
Posts: 8
Joined: 13 March 2006

Postby underquark » Fri Jun 09, 2006 5:30 pm

Pencil in the candidates for box 2 and you'll see that there must be an 8 in either r2c5 or r3c5. There can't, therefore, be an 8 anywhere else in that column.

Do the same sort of thing for the 9s in box 8 where either r7c4 or r7c5 must be a 9 but not r7c7 or r7c8.

Now look at row 6 - the numbers 1, 2 & 9 must go somewhere in columns 3, 4 & 5 so r6c6 must be 8.

Keep chipping away at it and patterns will emerge.
Last edited by underquark on Fri Jun 09, 2006 7:14 pm, edited 1 time in total.
underquark
 
Posts: 299
Joined: 06 September 2005

Postby Sped » Fri Jun 09, 2006 7:08 pm

Code: Select all
 *-----------*
 |.68|.52|.7.|
 |...|6.9|.5.|
 |...|..3|2.6|
 |---+---+---|
 |4.6|...|389|
 |859|346|127|
 |73.|...|564|
 |---+---+---|
 |.73|...|...|
 |.8.|237|...|
 |.9.|86.|73.|
 *-----------*

 *-----------------------------------------------------------*
 | 139   6     8     | 14    5     2     | 49    7     13    |
 | 123   124   1247  | 6     178   9     | 48    5     138   |
 | 159   14    1457  | 147   178   3     | 2     149   6     |
 |-------------------+-------------------+-------------------|
 | 4     12    6     | 157   127   15    | 3     8     9     |
 | 8     5     9     | 3     4     6     | 1     2     7     |
 | 7     3     12    | 19    1289  18    | 5     6     4     |
 |-------------------+-------------------+-------------------|
 | 1256  7     3     | 1459  19    145   | 4689  149   1258  |
 | 156   8     145   | 2     3     7     | 469   149   15    |
 | 125   9     1245  | 8     6     145   | 7     3     125   |
 *-----------------------------------------------------------*


This is a tough puzzle. From where you are, there are still a few easy things you can do.

There is just one place in row 3 for an 8, for instance. Then there'll be just one place for an 8 in box 5.

There are some exclusions on locked candidates, and a quad in row 7 (1459). Such simple steps take you only to here:


Code: Select all
 *-----------------------------------------------------------*
 | 139   6     8     | 14    5     2     | 49    7     13    |
 | 123   124   127   | 6     17    9     | 48    5     138   |
 | 159   14    157   | 147   8     3     | 2     149   6     |
 |-------------------+-------------------+-------------------|
 | 4     12    6     | 157   127   15    | 3     8     9     |
 | 8     5     9     | 3     4     6     | 1     2     7     |
 | 7     3     12    | 19    129   8     | 5     6     4     |
 |-------------------+-------------------+-------------------|
 | 26    7     3     | 159   19    145   | 68    14    28    |
 | 156   8     145   | 2     3     7     | 469   149   15    |
 | 125   9     1245  | 8     6     14    | 7     3     125   |
 *-----------------------------------------------------------*


I'm sure there's a more elegant solution, but I used the nice loop:

[r3c4]-1-[r2c5]-7-[r2c3]=7=[r3c3]=5=[r3c1]=9=[r3c8]-9-[r1c7]-4-[r1c4]-1-[r3c4] => r3c4<>1

To eliminate the 1 in r3c4, which set up the xy wing:

1-(r3c2)-4-(r3c4)-7-(r2c5)-1 which eliminates the 1s in r2c123

Which set up the XY wing:

1-(r6c3)-2-(r2c3)-7-(r2c5)-1 which eliminates the 1 in r6c5, leaving us here:

Code: Select all
 
 *-----------------------------------------------------------*
 | 139   6     8     | 14    5     2     | 49    7     13    |
 | 23    24    27    | 6     17    9     | 48    5     138   |
 | 159   14    157   | 47    8     3     | 2     149   6     |
 |-------------------+-------------------+-------------------|
 | 4     12    6     | 157   127   15    | 3     8     9     |
 | 8     5     9     | 3     4     6     | 1     2     7     |
 | 7     3     12    | 19    29    8     | 5     6     4     |
 |-------------------+-------------------+-------------------|
 | 26    7     3     | 159   19    145   | 68    14    28    |
 | 156   8     145   | 2     3     7     | 469   149   15    |
 | 125   9     1245  | 8     6     14    | 7     3     125   |
 *-----------------------------------------------------------*


Then the nice loop:

[r4c2]-1-[r6c3]-2-[r6c5]=2=[r4c5]=7=[r2c5]-7-[r2c3]-2-[r2c2]-4-[r3c2]-1-[r4c2] => r4c2<>1

eliminates the 1 in r4c2 and reduces the puzzle to singles.

Not an easy puzzle.
Sped
 
Posts: 126
Joined: 26 March 2006

Some UR eliminations

Postby keith » Fri Jun 09, 2006 8:47 pm

Sped wrote:
Code: Select all
*-----------------------------------------------------------*
 | 139e  6     8     | 14    5     2     | 49    7     13g   |
 | 123f  124   127   | 6     17    9     | 48    5     138h  |
 | 159   14    157   | 147   8     3     | 2     149   6     |
 |-------------------+-------------------+-------------------|
 | 4     12    6     | 157   127   15    | 3     8     9     |
 | 8     5     9     | 3     4     6     | 1     2     7     |
 | 7     3     12    | 19a   129c  8     | 5     6     4     |
 |-------------------+-------------------+-------------------|
 | 26    7     3     | 159b  19d   145   | 68    14    28    |
 | 156   8     145   | 2     3     7     | 469   149   15    |
 | 125   9     1245  | 8     6     14    | 7     3     125   |
 *-----------------------------------------------------------*

I don't have a "more elegant" solution, but let me point out a couple of unusual Unique Rectangle eliminations:

abcd is a potential UR on <19>. It is also an X-wing on <9>. In the solution, either ad = <9>, or bc = <9>. But bc = <9> forces the deadly soultion with ad = <1>, so ad must both be <9>.

efgh is a potential UR on <13>. It is also an X-wing on <3>. f cannot be <1>! Think of it this way: If g = <3>, f = <3> and is not <1>. If g = <1>, eh = <3>, and to avoid the deadly solution f cannot be <1>.

These reductions do not immediately solve this puzzle.

However, I think these types of reductions are far more common than most people realize. I also think they are easy to spot.

You can read more here:

http://forum.enjoysudoku.com/viewtopic.php?t=4204

Keith
keith
2017 Supporter
 
Posts: 209
Joined: 03 April 2006

Postby Mike Barker » Fri Jun 09, 2006 11:54 pm

I'm not sure I believe this, but after taking a slightly different route to the solution, there is what appears to be a Franken Squirmbag. To the best of my knowledge no apparant sighting of this creature has ever withstood closer examination, so the odds of this guy surviving are small, but here he is anyway!
Code: Select all
+----------------+---------------+----------------+
|  *19    6    8 |  *14    5   2 |   49    7    3 |
|    3  124  127 |    6  -17   9 |   48    5   18 |
|  159   14   57 |  147    8   3 |    2  149    6 |
+----------------+---------------+----------------+
|    4   12    6 |  -17  127   5 |    3    8    9 |
|    8    5    9 |    3    4   6 |    1    2    7 |
|    7    3  *12 |    9  *12   8 |    5    6    4 |
+----------------+---------------+----------------+
|   26    7    3 |    5    9 *14 |   68  *14   28 |
| *156    8 *145 |    2    3   7 |  469 *149  *15 |
| *125    9 *145 |    8    6 *14 |    7    3 *125 |
+----------------+---------------+----------------+

And yes, I know that two strong links will result eventually in the same eliminations, the question is, is there another fish that can perform the same trick?
Mike Barker
 
Posts: 458
Joined: 22 January 2006

Postby Havard » Sat Jun 10, 2006 12:58 am

what about this jellyfish?
Code: Select all
Franken-Jellyfish in columns: 2 4 8 9
19   6    8    | 14X  5    2    | 49   7    3
3    124X 127  | 6    17-  9    | 48   5    18X
159  14X  57   | 147X 8    3    | 2    149X 6
---------------+----------------+---------------
4    12X  6    | 17X  127  5    | 3    8    9
8    5    9    | 3    4    6    | 1    2    7
7    3    12   | 9    12   8    | 5    6    4
---------------+----------------+---------------
26   7    3    | 5    9    14   | 68   14X  28
156  8    145  | 2    3    7    | 469  149X 15X
125  9    145  | 8    6    14   | 7    3    125X

1  .  .  | 1X .  .  | .  .  .
.  1X 1  | .  1- .  | .  .  1X
1  1X .  | 1X .  .  | .  1X .
---------+----------+---------
.  1X .  | 1X 1  .  | .  .  .
.  .  .  | .  .  .  | 1  .  .
.  .  1  | .  1  .  | .  .  .
---------+----------+---------
.  .  .  | .  .  1  | .  1X .
1  .  1  | .  .  .  | .  1X 1X
1  .  1  | .  .  1  | .  .  1X


:)
Havard
Havard
 
Posts: 377
Joined: 25 December 2005

Another Solution

Postby Carcul » Sat Jun 10, 2006 10:06 am

Code: Select all
 *-----------------------------------------------------------*
 | 139   6     8     | 14    5     2     | 49    7     13    |
 | 123   124   127   | 6     17    9     | 48    5     138   |
 | 159   14    157   | 147   8     3     | 2     149   6     |
 |-------------------+-------------------+-------------------|
 | 4     12    6     | 157   127   15    | 3     8     9     |
 | 8     5     9     | 3     4     6     | 1     2     7     |
 | 7     3     12    | 19    129   8     | 5     6     4     |
 |-------------------+-------------------+-------------------|
 | 26    7     3     | 159   19    145   | 68    14    28    |
 | 156   8     145   | 2     3     7     | 469   149   15    |
 | 125   9     1245  | 8     6     14    | 7     3     125   |
 *-----------------------------------------------------------*

We have an Almost Nice Loop in cells {r127c19} if r1c1 is not "9":

[r1c7](=4=[r1c4])-9-[r1c1]-{Nice Loop: [r7c9]=2=[r7c1]-2-[r2c1]=(AUR:
r12c19)=2|8=[r2c9]-8-[r7c9]}-8-[r7c9]=8=[r2c9](-8-[r2c7]-4-[r3c8])=3=
=[r1c9]-3-[r1c1]-1-[r89c1]=1=[r89c3]-1-[r6c3]-2-[r6c5]=2=[r4c5]=7=
=[r2c5]=1=[r3c4]-1-[r3c8]-9-[r1c7], => r1c7<>9 and the puzzle is solved.

Carcul
Carcul
 
Posts: 724
Joined: 04 November 2005

A possible solution using the TIL Argument

Postby Carcul » Sat Jun 10, 2006 2:38 pm

(Refer to the grid I posted above)

-1-[r8c8]-{TILA: [r7c8](-1-[r8c9]-5-[r8c3])-1-[r7c456]=1=[r9c6]=4=
[r9c3]-4-[r8c3]-1-[r6c3]=1=[r4c2]=2=[r2c2]=4=[r2c7]=8|1=[r3c8]-1-
[r7c8], => r7c8<>1; [r7c8]-4-[r7c6]={Nice Loop: [r4c4]=7|9=[r7c4]-9-
[r7c5]-1-[r2c5]-7-[r3c4]=7=[r4c4]}=7=[r4c4]-7-[r3c4]=7=[r3c3]=5=
[r3c1]=9=[r1c1]-9-[r1c7]=9=[r3c8]-9-[r8c8]-4-[r7c8], => r7c8<>4 =>
r7c8=1}

So, r8c8 must be “1” and that solves the puzzle. The TILA (Two Incompa-
tible Loops Argument) is described here.

Carcul
Carcul
 
Posts: 724
Joined: 04 November 2005

Re: A possible solution using the TIL Argument

Postby r.e.s. » Sat Jun 10, 2006 10:20 pm

Carcul,

Thanks for breaking the above long chains into readable-length segments, but for many readers there's still a problem in the thread you mentioned.
r.e.s.
 
Posts: 337
Joined: 31 August 2005


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