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Mar 17 VH

 
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hughwill



Joined: 05 Apr 2010
Posts: 166
Location: Birmingham UK

PostPosted: Sun Mar 17, 2013 10:50 am    Post subject: Mar 17 VH Reply with quote

After basics:

Code:

+--------------+----------------+---------------+
| 678 1678 9   | 1278 4    5    | 3    126 27   |
| 4   167  36  | 9    17   1237 | 156  8   257  |
| 378 2    5   | 6    178  137  | 19   4   79   |
+--------------+----------------+---------------+
| 9   68   7   | 1258 1568 12   | 45   3   245  |
| 1   4    2   | 57   3    79   | 8    59  6    |
| 5   3    68  | 248  689  249  | 7    29  1    |
+--------------+----------------+---------------+
| 38  9    348 | 15   15   6    | 2    7   48   |
| 2   5    46  | 47   79   8    | 1469 16  3    |
| 678 678  1   | 3    2    49   | 4569 56  4589 |
+--------------+----------------+---------------+

Play this puzzle online at the Daily Sudoku site

I couldn't do it in one:

Quote:
3 XY Wings- 479 pivot r9c6, 468 pivot r6c3 and 169 pivot r9c7


But a bit more interesting than most previous VHs.

Hugh
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Marty R.



Joined: 12 Feb 2006
Posts: 5121
Location: Rochester, NY, USA

PostPosted: Sun Mar 17, 2013 3:15 pm    Post subject: Reply with quote

I had the identical solution as yours.
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JC Van Hay



Joined: 13 Jun 2010
Posts: 364
Location: Charleroi, Belgium

PostPosted: Sun Mar 17, 2013 6:52 pm    Post subject: Reply with quote

Code:
+----------------+--------------------+--------------------+
| 678  1678  9   | 1278  4     5      | 3     16(2)  27    |
| 4    167   36  | 9     17    137(2) | 156   8      57(2) |
| 378  2     5   | 6     178   137    | 19    4      79    |
+----------------+--------------------+--------------------+
| 9    68    7   | 1258  1568  12     | 45    3      245   |
| 1    4     2   | 57    3     79     | 8     59     6     |
| 5    3     68  | 248   689   49-2   | 7     9(2)   1     |
+----------------+--------------------+--------------------+
| 38   9     348 | 15    15    6      | 2     7      48    |
| 2    5     46  | 47    79    8      | 1469  16     3     |
| 678  678   1   | 3     2     49     | 4569  56     4589  |
+----------------+--------------------+--------------------+
[Kite(2R2C8) :=> NP(49)r69c6] or [XYW(49-7)r9c6 :=> -7r5c4]; 7 Singles
Skyscraper(6C18) :=> r8c3=4;ste
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arkietech



Joined: 31 Jul 2008
Posts: 1708
Location: Northwest Arkansas USA

PostPosted: Sun Mar 17, 2013 8:57 pm    Post subject: Reply with quote

Code:
 *-----------------------------------------------------------*
 | 678   1678  9     | 1278  4     5     | 3     126   27    |
 | 4     167   36    | 9     17    1237  | 156   8     257   |
 | 378   2     5     | 6     178   137   | 19    4     79    |
 |-------------------+-------------------+-------------------|
 | 9     68    7     | 1258  1568  12    | 45    3     245   |
 | 1     4     2     | 57    3     79    | 8     59    6     |
 | 5     3     68    | 248   689   249   | 7     29    1     |
 |-------------------+-------------------+-------------------|
 | 38    9     348   | 15    15    6     | 2     7     48    |
 | 2     5     46    | 47    79    8     | 1469  16    3     |
 | 678   678   1     | 3     2     49    | 4569  56    4589  |
 *-----------------------------------------------------------*
net
6r1c8 6r9c1 7r9c2       8r9c9
6r8c8 4r8c3       4r7c9 8r9c9
6r9c8 5r5c8 4r4c7 4r7c9 8r9c9
=> 8r9c9; ste
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JC Van Hay



Joined: 13 Jun 2010
Posts: 364
Location: Charleroi, Belgium

PostPosted: Mon Mar 18, 2013 8:37 am    Post subject: Reply with quote

Dan, could you check the third line of your net ? It leads to r79c9=48 and not r7c9=4+r9c9=8!
JC
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arkietech



Joined: 31 Jul 2008
Posts: 1708
Location: Northwest Arkansas USA

PostPosted: Mon Mar 18, 2013 12:31 pm    Post subject: Reply with quote

JC Van Hay wrote:
Dan, could you check the third line of your net ? It leads to r79c9=48 and not r7c9=4+r9c9=8!
JC


HELP! I feel foolish but I don't see it.. Confused

Code:
 *-----------------------------------------------------------*
 | 678   1678  9     | 1278  4     5     | 3     126   27    |
 | 4     167   36    | 9     17    1237  | 156   8     257   |
 | 378   2     5     | 6     178   137   | 19    4     79    |
 |-------------------+-------------------+-------------------|
 | 9     68    7     | 1258  1568  12    |(4)5   3     25-4  |
 | 1     4     2     | 57    3     79    | 8     (5)9  6     |
 | 5     3     68    | 248   689   249   | 7     29    1     |
 |-------------------+-------------------+-------------------|
 | 38    9     348   | 15    15    6     | 2     7     (4)8  |
 | 2     5     46    | 47    79    8     | 1469  16    3     |
 | 678   678   1     | 3     2     49    | 4569  5(6)  45(8)9|
 *-----------------------------------------------------------*
net
6r1c8 6r9c1 7r9c2       8r9c9
6r8c8 4r8c3       4r7c9 8r9c9
6r9c8 5r5c8 4r4c7 4r7c9 8r9c9
=> 8r9c9; ste
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JC Van Hay



Joined: 13 Jun 2010
Posts: 364
Location: Charleroi, Belgium

PostPosted: Wed Mar 20, 2013 9:00 am    Post subject: Reply with quote

Dan,
Your net may be written as a "Kraken 6 Column 8", as follows ...
Code:
+---------------------+------------------+-----------------------+
| 78(6)  1678   9     | 1278  4     5    | 3      12(6)  27      |
| 4      167    36    | 9     17    1237 | 156    8      257     |
| 378    2      5     | 6     178   137  | 19     4      79      |
+---------------------+------------------+-----------------------+
| 9      68     7     | 1258  1568  12   | (45)   3      25(-4)  |
| 1      4      2     | 57    3     79   | 8      9(5)   6       |
| 5      3      68    | 248   689   249  | 7      29     1       |
+---------------------+------------------+-----------------------+
| 38     9      38(4) | 15    15    6    | 2      7      (48)    |
| 2      5      (46)  | 47    79    8    | 169-4  1(6)   3       |
| (678)  6(78)  1     | 3     2     49   | 59-46  (56)   -59(48) |
+---------------------+------------------+-----------------------+
6r1c8-6r1c1=(6-7)r9c1=(7-8)r9c2=NP(84)r79c9
||
6r8c8-(6=4)r8c3-4r7c3=NP(48)r79c9
||
6r9c8-5r9c8=5r5c8-(5=4)r4c7-4r7c9=NP(48)r79c9

-> r79c9=48 (or -59r79c9) :=> -4r4c9.r89c7 [+ -6r9c7 due to the use of the included FXW(6C18)]

A simpler interpretation of these eliminations is given by the following "6-SIS chain" ...
Code:
+--------------------+------------------+--------------------+
| 78(6)  1678  9     | 1278  4     5    | 3      12(6)  27   |
| 4      167   36    | 9     17    1237 | 156    8      257  |
| 378    2     5     | 6     178   137  | 19     4      79   |
+--------------------+------------------+--------------------+
| 9      68    7     | 1258  1568  12   | (45)   3      25-4 |
| 1      4     2     | 57    3     79   | 8      9(5)   6    |
| 5      3     68    | 248   689   249  | 7      29     1    |
+--------------------+------------------+--------------------+
| 38     9     38(4) | 15    15    6    | 2      7      8(4) |
| 2      5     (46)  | 47    79    8    | 169-4  1(6)   3    |
| 78(6)  678   1     | 3     2     49   | 59-46  (56)   4589 |
+--------------------+------------------+--------------------+

Chain[6] : (4=5)r4c7-5r5c8=5r9c8-Finned XWing[6r9c8=Skyscraper(6r19c1.r18c8)]-(6=4)r8c3-4r7c3=4r7c9 :=> -6r9c6(from the included FXW),-4r4c9.4r89c7(->r79c9=48 )
JC
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arkietech



Joined: 31 Jul 2008
Posts: 1708
Location: Northwest Arkansas USA

PostPosted: Wed Mar 20, 2013 1:41 pm    Post subject: Reply with quote

JC Van Hay wrote:
6r1c1=(6-7)r9c1=(7-8)r9c2=NP(84)r79c9
||
6r8c8-(6=4)r8c3-4r7c3=NP(48)r79c9
||
6r9c8-5r9c8=5r5c8-(5=4)r4c7-4r7c9=NP(48)r79c9

-> r79c9=48 (or -59r79c9) :=> -4r4c9.r89c7 [+ -6r9c7 due to the use of the included FXW(6C18)]


NP(48)r79c9 doesn't solve the puzzle.

How about


Code:
 *-----------------------------------------------------------*
 | 678   1678  9     | 1278  4     5     | 3     126   27    |
 | 4     167   36    | 9     17    1237  | 156   8     257   |
 | 378   2     5     | 6     178   137   | 19    4     79    |
 |-------------------+-------------------+-------------------|
 | 9     68    7     | 1258  1568  12    |(4)5   3     25-4  |
 | 1     4     2     | 57    3     79    | 8     (5)9  6     |
 | 5     3     68    | 248   689   249   | 7     29    1     |
 |-------------------+-------------------+-------------------|
 | 38    9     348   | 15    15    6     | 2     7     (4)8  |
 | 2     5     46    | 47    79    8     | 1469  16    3     |
 | 678   678   1     | 3     2     49    | 4569  5(6)  45(8)9|
 *-----------------------------------------------------------*
net
6r1c8 6r9c1 7r9c2       8r9c9
6r8c8 4r8c3       4r7c9 8r9c9
6r9c8 5r5c8 4r4c7 4r7c9 8r9c9

6r1c8-r1c1=(6-7)r9c1=(7-8)r9c2=8r9c9
||
6r8c8-(6=4)r8c3-r7c3=(4-8)r7c9=8r9c9
||
(6-5)r9c8=r5c8-(5=4)r4c7-4r4c9=(4-8)r7c9=8r9c9 => 8r9c9;
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JC Van Hay



Joined: 13 Jun 2010
Posts: 364
Location: Charleroi, Belgium

PostPosted: Wed Mar 20, 2013 3:52 pm    Post subject: Reply with quote

Dan, in column 9, you are forgetting 4r9c9. Thus, in your third line, -4r4c9 -> +4r79c9 and not +4r7c9!
JC
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arkietech



Joined: 31 Jul 2008
Posts: 1708
Location: Northwest Arkansas USA

PostPosted: Wed Mar 20, 2013 6:46 pm    Post subject: Reply with quote

JC Van Hay wrote:
Dan, in column 9, you are forgetting 4r9c9. Thus, in your third line, -4r4c9 -> +4r79c9 and not +4r7c9!
JC


Thanks JC Embarassed

I finally see it.
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RobertRattley



Joined: 24 Jun 2007
Posts: 53
Location: Australia

PostPosted: Mon Mar 25, 2013 10:59 am    Post subject: Reply with quote

Back to the first two posts:

Yes, I found the same three xy wings.

It took me a frustratingly long time to find even the first xy wing, because I had missed an elimination or two, in the "fairly hard" category.

I remain in awe of whoever can construct (or discover) such beautiful puzzles.
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