The New Sudoku Players' Forum

[ArkieTech]

Code: Select all

 *-----------*
 |.4.|7..|..2|
 |1..|8..|...|
 |..9|.6.|3..|
 |---+---+---|
 |.2.|...|5..|
 |6.8|.5.|4.1|
 |..4|...|.9.|
 |---+---+---|
 |..3|.4.|8..|
 |...|..2|..7|
 |7..|..6|.5.|
 *-----------*


Play/Print this puzzle online

[Leren]

Code: Select all

*---------------------------------------------------------------*
| 358   4     56     | 7      139   1359   | 169   168   2      |
| 1     3567 e567-2  | 8     a239   3459   | 679   467   569    |
| 258   57    9      | 124    6     145    | 3     1478  58     |
|--------------------+---------------------+--------------------|
| 39    2    d17     | 13469 c1379  13489  | 5     678   368    |
| 6     379   8      | 239    5     39     | 4     27    1      |
| 35    1357  4      | 1236  b1237  138    | 267   9     368    |
|--------------------+---------------------+--------------------|
| 259   1569  3      | 159    4     7      | 8     126   69     |
| 4     15689 156    | 159    189   2      | 169   3     7      |
| 7     189   12     | 139    1389  6      | 129   5     4      |
*---------------------------------------------------------------*

L2 Wing: (2) r2c5 = (2-7) r6c5 = r4c5 - r4c3 = (7) r2c3 => - 2 r2c3; stte

Leren

[pjb]

Code: Select all

 358    4      56     | 7      139    1359   | 169    168    2     
 1      3567   2567   | 8      239    3459   | 679    467    569   
 258    57     9      | 124    6      145    | 3      1478   58     
 ---------------------+----------------------+---------------------
 39     2     a17     | 13469  1379   13489  | 5      68-7   368   
 6      39-7   8      | 239    5      39     | 4     e27     1     
 35     1357   4      | 1236   1237   138    | 267    9      368   
 ---------------------+----------------------+---------------------
c259    1569   3      | 159    4      7      | 8     d126    69     
 4      15689  156    | 159    189    2      | 169    3      7     
 7      189   b12     | 139    1389   6      | 129    5      4     


(7=1) r4c3 - (1=2) r9c3 - r7c1 = r7c8 - (2=7) r5c8 => -7 r4c8, r5c2; stte

Phil
(Silly typo fixed)

[SteveG48]

Code: Select all

 *--------------------------------------------------------------------*
 | 358    4      56     | 7      139    1359   | 169    168    2      |
 | 1      3567  d2567   | 8     e239    3459   | 679    467    569    |
 |c258    57     9      |f124    6      145    | 3      1478   58     |
 *----------------------+----------------------+----------------------|
 | 39     2     j17     | 13469 i1379   13489  | 5      678    368    |
 | 6      379    8      |g239    5      39     | 4      27     1      |
 | 35     1357   4      |g1236  h1237   138    | 267    9      368    |
 *----------------------+----------------------+----------------------|
 |b259    1569   3      | 159    4      7      | 8      126    69     |
 | 4      15689  156    | 159    189    2      | 169    3      7      |
 | 7      189   a2-1    | 139    1389   6      | 129    5      4      |
 *--------------------------------------------------------------------*


(1-2)r9c3 = r7c1 - r3c1= r2c3 - r2c5 = r3c4 - r56c4 = (2-7)r6c5 = r4c5 - (7=1)r4c3 => -1 r9c3 ; stte

[tlanglet]

After basics, I started looking for Sue de Coq patterns and found this
Almost Sue de Cue (13459)r123c6 with (39)r5c6 & (14=2)r3c4.

Code: Select all

 *--------------------------------------------------------------------*
 | 358    4      56     | 7      139   *1359   | 169    168    2      |
 | 1      3567  b2567   | 8     a239   *3459   | 679    467    569    |
 | 258    57     9      |*14=2   6     *145    | 3      1478   58     |
 |----------------------+----------------------+----------------------|
 | 39     2     c17     | 13469  1379   13489  | 5      678    368    |
 | 6     d379    8      |d239    5    *d39     | 4      27     1      |
 | 35     1357   4      | 1236   1237   138    | 267    9      368    |
 |----------------------+----------------------+----------------------|
 | 259    1569   3      | 159    4      7      | 8      126    69     |
 | 4      15689  156    | 159    189    2      | 169    3      7      |
 | 7      189    12     | 139    1389   6      | 129    5      4      |
 *--------------------------------------------------------------------*


The Sue de Coq makes the following deletions: Sue de Cue (13459)r123c6 => r46c6<>3, r4c6<>9, r1c5<>1

Pursuing the extra term: 2r2c4-r3c1=(2-7)r2c3=7r4c3-(7=392)r5c264 Contradiction => r3c4<>2

Thus, the SdC is true but does not solve the puzzle. However the deletion of 2 in r3c4 does complete the puzzle. It is sad when a beautiful pattern fails to complete a puzzle but a side aspect of the pattern does the deed.

Ted

[Edited to correct typo in SdC deletions.]

[Marty R.]

Code: Select all

 358    4      56     | 7      139    1359   | 169    168    2     
 1      3567   2567   | 8      239    3459   | 679    467    569   
 258    57     9      | 124    6      145    | 3      1478   58     
 ---------------------+----------------------+---------------------
 39     2     a17     | 13469  1379   13489  | 5      68-7   368   
 6      379    8      | 239    5      39     | 4     e27     1     
 35     135-7  4      | 1236   1237   138    | 267    9      368   
 ---------------------+----------------------+---------------------
c259    1569   3      | 159    4      7      | 8     d126    69     
 4      15689  156    | 159    189    2      | 169    3      7     
 7      189   b12     | 139    1389   6      | 129    5      4     


(7=1) r4c3 - (1=2) r9c3 - r7c1 = r7c8 - (2=7) r5c8 => -7 r4c8, r5c2; stte

Phil

Same as Phil except Phil seems to have a typo, showing the 7 being eliminated from r6c2 rather than r5c2.

[Luke]

Much same as others, but inspired by Ted's doubly-linked als:

Code: Select all

*--------------------------------------------------------------------*
 | 358    4      56     | 7      139    1359   | 169    168    2      |
 | 1      3567  *2567   | 8     *239    3459   | 679    467    569    |
 | 258    57     9      | 14-2   6      145    | 3      1478   58     |
 |----------------------+----------------------+----------------------|
 | 39     2     *17     | 13469  1379   13489  | 5      678    368    |
 | 6     *379    8      |*239    5      39     | 4     *27     1      |
 | 35     1357   4      | 1236   1237   138    | 267    9      368    |
 |----------------------+----------------------+----------------------|
 | 259    1569   3      | 159    4      7      | 8      126    69     |
 | 4      15689  156    | 159    189    2      | 169    3      7      |
 | 7      189    12     | 139    1389   6      | 129    5      4      |
 *--------------------------------------------------------------------*

(2)r5c4=(2-7)r5c8=r5c2-r4c3=(7-2)r2c3=(2)r2c5 ==>r3c4<>2

Ted: I don't think (1)r1c6 is part of the SdQ elims, unless there's a cannibal in the house...

Edit: K, it's just a typo, ne'er mind.

[Ngisa]

Code: Select all

+----------------+------------------+--------------+
| 358 4     56   | 7     139  1359  | 169 168  2   |
| 1   3567  2567 | 8     239  3459  | 679 467  569 |
| 258 57    9    | 124   6    145   | 3   1478 58  |
+----------------+------------------+--------------+
| 39  2     7-1   | 13469 1379 13489 | 5   678  368 |
| 6   7-39   8    | 239   5    39    | 4   27   1   |
| 35  1357  4    | 1236  1237 138   | 267 9    368 |
+----------------+------------------+--------------+
| 259 1569  3    | 159   4    7     | 8   126  69  |
| 4   15689 156  | 159   189  2     | 169 3    7   |
| 7   189   12   | 139   1389 6     | 129 5    4   |
+----------------+------------------+--------------+


2r5c8 => 7r5c2
2r5c8-r7c8=2r9c7-(2=1)r9c3 =>7r4c3; two 7's in Box 4; r5c8<>2; stte

[SteveG48]

Code: Select all

+----------------+------------------+--------------+
| 358 4     56   | 7     139  1359  | 169 168  2   |
| 1   3567  2567 | 8     239  3459  | 679 467  569 |
| 258 57    9    | 124   6    145   | 3   1478 58  |
+----------------+------------------+--------------+
| 39  2     7-1   | 13469 1379 13489 | 5   678  368 |
| 6   7-39   8    | 239   5    39    | 4   27   1   |
| 35  1357  4    | 1236  1237 138   | 267 9    368 |
+----------------+------------------+--------------+
| 259 1569  3    | 159   4    7     | 8   126  69  |
| 4   15689 156  | 159   189  2     | 169 3    7   |
| 7   189   12   | 139   1389 6     | 129 5    4   |
+----------------+------------------+--------------+


2r5c8 => 7r5c2
2r5c8-r7c8=2r9c7-(2=1)r9c3 =>7r4c3; two 7's in Box 4; r5c8<>2; stte

Good one, Ngisa. If you want to write exactly the same thing as a loop, try:

(2)r5c8 -r7c8 =r9c7 - (2=1)r9c3 - (1=7)r4c3 - r5c2 = (7-2)r5c8 => -2 r5c8

[ronk]

The Sue de Coq makes the following deletions: Sue de Cue (13459)r123c6 => r46c6<>3, r4c6<>9, r1c5<>1

Pursuing the extra term: 2r2c4-r3c1=(2-7)r2c3=7r4c3-(7=392)r5c264 Contradiction => r3c4<>2

Thus, the SdC is true but does not solve the puzzle. However the deletion of 2 in r3c4 does complete the puzzle. It is sad when a beautiful pattern fails to complete a puzzle but a side aspect of the pattern does the deed.

So your chain ... (2)r3c1=(2-7)r2c3=(7)r4c3-(7=392)r5c264 => r3c4<>2 ... is sufficient for ste, right?

Moreover, if there truly were an almost SDC, both the SDC without the extra candidate(s), and the extra candidate(s), should separately lead to the same exclusion(s).

[tlanglet]

The Sue de Coq makes the following deletions: Sue de Cue (13459)r123c6 => r46c6<>3, r4c6<>9, r1c5<>1

Pursuing the extra term: 2r2c4-r3c1=(2-7)r2c3=7r4c3-(7=392)r5c264 Contradiction => r3c4<>2

Thus, the SdC is true but does not solve the puzzle. However the deletion of 2 in r3c4 does complete the puzzle. It is sad when a beautiful pattern fails to complete a puzzle but a side aspect of the pattern does the deed.

So your chain ... (2)r3c1=(2-7)r2c3=(7)r4c3-(7=392)r5c264 => r3c4<>2 ... is sufficient for ste, right?

Moreover, if there truly were an almost SDC, both the SDC without the extra candidate(s), and the extra candidate(s), should separately lead to the same exclusion(s).

Ron,

So your chain ... (2)r3c1=(2-7)r2c3=(7)r4c3-(7=392)r5c264 => r3c4<>2 ... is sufficient for ste, right?
Yes, the chain => r3c4<>2 results in ste.

Moreover, if there truly were an almost SDC, both the SDC without the extra candidate(s), and the extra candidate(s), should separately lead to the same exclusion(s).

I am not sure exactly what you intended by your post. I understand that the only deletions possible from an almost solution with a valid extra candidate(s) is that common set of deletions provided by both the extra candidate(s) and the solution without the extra candidate. When the extra candidate is invalid, as is the situation this puzzle, I have simply deleted the invalid extra candidate plus made the deletions of the basic solution which might be considered as a two step process.

Are you addressing a consideration that I have totally overlooked?

Ted

[Ngisa]

Steve, I have followed the loop as you have shown. It elaborates it better and clear. Next time I will try to do that. Thanks.

[ronk]

I am not sure exactly what you intended by your post. I understand that the only deletions possible from an almost solution with a valid extra candidate(s) is that common set of deletions provided by both the extra candidate(s) and the solution without the extra candidate. When the extra candidate is invalid, as is the situation this puzzle, I have simply deleted the invalid extra candidate plus made the deletions of the basic solution which might be considered as a two step process.

Are you addressing a consideration that I have totally overlooked?

Probably not. Minor point I suppose, but I'm only saying that you found an SDC while looking for an almost SDC. Your post makes it sound like you actually found an almost SDC.