Vanhegan extreme December 18, 2012

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Vanhegan extreme December 18, 2012

Postby ArkieTech » Tue Dec 18, 2012 8:48 am

Code: Select all
 *-----------*
 |..7|..5|26.|
 |6.3|...|4..|
 |54.|...|.13|
 |---+---+---|
 |2..|.1.|...|
 |...|9.4|...|
 |...|.5.|..8|
 |---+---+---|
 |17.|...|.54|
 |..2|...|6.1|
 |.95|1..|8..|
 *-----------*


Play/Print this puzzle online
dan
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Re: Vanhegan extreme December 18, 2012

Postby Leren » Tue Dec 18, 2012 9:47 am

Code: Select all
*--------------------------------------------------------------------------------*
| 8       1       7        | 4       3       5        | 2       6       9        |
| 6       2       3        | 7       9       1        | 4       8       5        |
| 5       4       9        | 268     268     28       | 7       1       3        |
|--------------------------+--------------------------+--------------------------|
| 2       356     48       | 368     1       378      | 359     3479    67       |
| 7       356    a18       | 9      b268     4        |A35-1   B23     c26       |
| 9       36      14       | 236     5       237      |d13      2347    8        |
|--------------------------+--------------------------+--------------------------|
| 1       7       6        | 238     28      2389     | 39      5       4        |
| 34      8       2        | 5       47      39       | 6       379     1        |
| 34      9       5        | 1       47      6        | 8       237     27       |
*--------------------------------------------------------------------------------*


ALS Pair Exclusion : 1 is excluded from cell pair AB by cells marked a-d; stte

I've no idea how to Eureka this move - any suggestions ?

Leren
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Re: Vanhegan extreme December 18, 2012

Postby SudoQ » Tue Dec 18, 2012 10:22 am

Another move (with fewer cells involved):
Code: Select all
|-------------|----------------|---------------|
| 8   1    7  | 4    3    5    | 2    6     9  |
| 6   2    3  | 7    9    1    | 4    8     5  |
| 5   4    9  | 268  268  28   | 7    1     3  |
|-------------|----------------|---------------|
| 2   356  48 | 368  1    378  | 359  3479  67 |
| 7  (35)6 18 | 9    268  4    |(135) 2(3)  26 |
| 9   36   14 | 236  5    237  |(1)-3 2347  8  |
|-------------|----------------|---------------|
| 1   7    6  | 238  28   2389 | 39   5     4  |
| 34  8    2  | 5    47   39   | 6    379   1  |
| 34  9    5  | 1    47   6    | 8    237   27 |
|-------------|----------------|---------------|
/SudoQ
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Re: Vanhegan extreme December 18, 2012

Postby David P Bird » Tue Dec 18, 2012 11:01 am

Leren wrote:
Code: Select all
*--------------------------------------------------------------------------------*
| 8       1       7        | 4       3       5        | 2       6       9        |
| 6       2       3        | 7       9       1        | 4       8       5        |
| 5       4       9        | 268     268     28       | 7       1       3        |
|--------------------------+--------------------------+--------------------------|
| 2       356     48       | 368     1       378      | 359     3479    67       |
| 7       356    a18       | 9      b268     4        |A35-1   B23     c26       |
| 9       36      14       | 236     5       237      |d13      2347    8        |
|--------------------------+--------------------------+--------------------------|
| 1       7       6        | 238     28      2389     | 39      5       4        |
| 34      8       2        | 5       47      39       | 6       379     1        |
| 34      9       5        | 1       47      6        | 8       237     27       |
*--------------------------------------------------------------------------------*
ALS Pair Exclusion : 1 is excluded from cell pair AB by cells marked a-d; stte

I've no idea how to Eureka this move - any suggestions ?

When a house contains multiple bilocals and bivalues there are always many ways of forming ANS/AHS complementary sets.

At the heart of row 5 there is an (268)ANS:r5c59 which gives

(1=3)r6c7 - (3=2)r5c8 - (26=8)ANS:r5c59 - (8=1)r5c3 => r5c7 <> 1 (7 links)

If any of the member candidates exists in a further bivalue cell, that cell can be added to the ANS.
Adding (18)r5c3:

(1=3)r6c7 - (3=2)r5c8 - (268=1)ANS:r5c359 => r5c7 <> 1 (5 links)

Adding (23)r5c8

(1=3)r6c7 - (2368=1)ANS:r5c3589 => r5c7 (3 links)

Note that r5c7 is not involved in the pattern, only the elimination.

It depends on whether you take any prisoners or not as to how to notate it - the bigger the ANS the more likely it is that an inexperienced reader will stumble. This also puts into question the merit of judging chains just by their link counts.

PS I went for the Deadly Pattern:

(9)r8c8 =[(347)DP:r89c148]= (2)r9c8 - (2=3)r5c8 - (3)r456c7 = (3)r7c7 => r7c7 <> 9
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Re: Vanhegan extreme December 18, 2012

Postby ArkieTech » Tue Dec 18, 2012 1:08 pm

Code: Select all
 *-----------------------------------------------------------*
 | 8     1     7     | 4     3     5     | 2     6     9     |
 | 6     2     3     | 7     9     1     | 4     8     5     |
 | 5     4     9     | 268   268   28    | 7     1     3     |
 |-------------------+-------------------+-------------------|
 | 2     356   48    | 368   1     378   | 359   3479  67    |
 | 7    c356   18    | 9     268   4     |*35-1 b23    26    |
 | 9     36    14    | 236   5     237   |a13    2347  8     |
 |-------------------+-------------------+-------------------|
 | 1     7     6     | 238   28    2389  | 39    5     4     |
 | 34    8     2     | 5     47    39    | 6     379   1     |
 | 34    9     5     | 1     47    6     | 8     237   27    |
 *-----------------------------------------------------------*
H-wing *=bd
(1=3)r6c7-3r5c78=(3-5)r5c2=5r5c7 => -1r5c7; stte
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Re: Vanhegan extreme December 18, 2012

Postby Marty R. » Tue Dec 18, 2012 7:46 pm

I went for the DP as well and don't know if the notation I used is acceptable.

(9r8c8=2r9c8)-(1235=9)r5c78,r6c7,r4c7=>r7c7<>9
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Re: Vanhegan extreme December 18, 2012

Postby tlanglet » Tue Dec 18, 2012 8:56 pm

Same, same..............

BUG_Lite+2(347)r89c158[3r7c7=(7-2)r9c9]=r5c9-(2=3)r5c8 => r456c7<>3

Ted
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Re: Vanhegan extreme December 18, 2012

Postby tlanglet » Tue Dec 18, 2012 9:03 pm

Marty R. wrote:I went for the DP as well and don't know if the notation I used is acceptable.

(9r8c8=2r9c8)-(1235=9)r5c78,r6c7,r4c7=>r7c7<>9


Marty,

Your notation is fine by me except you do need to indicate the basis of the first strong link, which in this case is the potential DP. Note that David had one format and I used an alternate format to provide that detail. I am not aware of a "standard" notation to handle these types of circumstances.

Ted
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Re: Vanhegan extreme December 18, 2012

Postby storm_norm22 » Tue Dec 18, 2012 9:13 pm

all respect to mr vanhegan for his site, producing a wide range of puzzles but it kind of shows you how far the community has come in solving techniques that can reduce this "extreme" puzzle in one step after basics. one of the more fascinating aspects of the sudoku community in my eyes.
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Re: Vanhegan extreme December 18, 2012

Postby pjb » Tue Dec 18, 2012 10:19 pm

A simple xy chain does the job just fine:
(1=8)r5c3-(8=6)r5c5-(6=2)r5c9-(2=3)r5c8-(3=1)r6c7 => -1r5c7, -1r6c3; stte

interestingly, same cells, same result for the 1-4 ALS: A: 12368 at r5c3589; B: 13 at r6c7; X=3; Z=1.
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Re: Vanhegan extreme December 18, 2012

Postby Leren » Tue Dec 18, 2012 10:35 pm

(9) r4c7 = 2 r5c8 [(12359)ANS r456c7, r5c8] - 2 r9c8 = 9 r8c8 [(347)DP:r89c148] = > r7c7, r4c8 <9>

How could I have missed something so obvious :D

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Re: Vanhegan extreme December 18, 2012

Postby Leren » Tue Dec 18, 2012 10:53 pm

pjb wrote: A simple xy chain does the job just fine:
(1=8)r5c3-(8=6)r5c5-(6=2)r5c9-(2=3)r5c8-(3=1)r6c7 => -1r5c7, -1r6c3; stte


The other PM's have 268 in r5c5. Did we miss something ?

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Re: Vanhegan extreme December 18, 2012

Postby pjb » Tue Dec 18, 2012 11:28 pm

Apologies: I forgot that I had previously found the chain (2=3)r5c8-(3=1)r6c7-r5c7=(1)r5c3=(8)r5c5=(8=2)r7c5 =>r5c5 <> 2.

However, the ALS works fine whether r5c5 is 268 or 68.
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Re: Vanhegan extreme December 18, 2012

Postby daj95376 » Wed Dec 19, 2012 12:46 am

Leren wrote:
Code: Select all
*--------------------------------------------------------------------------------*
| 8       1       7        | 4       3       5        | 2       6       9        |
| 6       2       3        | 7       9       1        | 4       8       5        |
| 5       4       9        | 268     268     28       | 7       1       3        |
|--------------------------+--------------------------+--------------------------|
| 2       356     48       | 368     1       378      | 359     3479    67       |
| 7       356    a18       | 9      b268     4        |A35-1   B23     c26       |
| 9       36      14       | 236     5       237      |d13      2347    8        |
|--------------------------+--------------------------+--------------------------|
| 1       7       6        | 238     28      2389     | 39      5       4        |
| 34      8       2        | 5       47      39       | 6       379     1        |
| 34      9       5        | 1       47      6        | 8       237     27       |
*--------------------------------------------------------------------------------*


ALS Pair Exclusion : 1 is excluded from cell pair AB by cells marked a-d; stte

Hmmm! I don't see it. For example, I don't see B=1, if it existed, creating a conflict in your six cells.

Code: Select all
B=1 _ ( d=3 ,  A=5  )
    _ ( a=8 , bc=26 )
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Re: Vanhegan extreme December 18, 2012

Postby Leren » Wed Dec 19, 2012 1:10 am

daj 95376 Wrote: Hmmm! I don't see it. For example, I don't see B=1, if it existed, creating a conflict in your six cells.


The way this move works is as follows:

If A is 1 and B is 3 then d = nothing! = > conflict.

If A is 1 and B is 2 then c is 6, b is 8 and a is ... nothing! = > conflict.

Thus whatever the value of B, A cannot be 1 = > A cannot be 1.

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