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Free Press Thu 17 Dec 2015

 
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keith



Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA

PostPosted: Mon Feb 15, 2016 8:00 pm    Post subject: Free Press Thu 17 Dec 2015 Reply with quote

The Free Press puzzles have gotten much more interesting. Now, the Thu and Sun puzzles often need advanced moves, while the Fri one needs chains.
Code:
+-------+-------+-------+
| . . 7 | . . . | 9 5 . |
| . . . | . 1 . | . . . |
| . . . | . . 7 | . 3 2 |
+-------+-------+-------+
| . 3 . | . . . | 4 1 . |
| 7 . . | 6 . 2 | . . 8 |
| . 9 5 | . . . | . 7 . |
+-------+-------+-------+
| 3 4 . | 9 . 5 | . . . |
| . . . | . 2 8 | . . . |
| . . 9 | . . . | 6 . . |
+-------+-------+-------+


Keith
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Marty R.



Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA

PostPosted: Mon Feb 15, 2016 9:45 pm    Post subject: Reply with quote

Code:

+-------------+------------+----------+
| 1   28  7   | 238 38  6  | 9  5  4  |
| 9   25  3   | 25  1   4  | 8  6  7  |
| 4   568 68  | 58  9   7  | 1  3  2  |
+-------------+------------+----------+
| 268 3   268 | 78  578 9  | 4  1  56 |
| 7   1   4   | 6   35  2  | 35 9  8  |
| 68  9   5   | 14  348 13 | 2  7  36 |
+-------------+------------+----------+
| 3   4   28  | 9   6   5  | 7  28 1  |
| 56  67  1   | 37  2   8  | 35 4  9  |
| 258 78  9   | 14  347 13 | 6  28 35 |
+-------------+------------+----------+

Play this puzzle online at the Daily Sudoku site
This one's a Thursday, so presumably an advanced move could do it, but I didn't find it, so here's my chain.

(7=6)r8c2-(6=5)r8c1-(5=3)r8c7-r5c7=r5c5-(3=1487)b5p7891=> -7r8c4

P.S. A note on the notation of the last term, which I haven't yet seen on this forum. b=box, p=point or position, referring to the position of the cells in the box, 1-9 going left to right and down. This is an excellent shortcut for an ALS within a box.
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JC Van Hay



Joined: 13 Jun 2010
Posts: 494
Location: Charleroi, Belgium

PostPosted: Mon Feb 15, 2016 9:59 pm    Post subject: Reply with quote

Just for the fun :
Code:
+-------------------+--------------+---------------+
| 1      28   7     | 238  38   6  | 9   5     4   |
| 9      25   3     | 25   1    4  | 8   6     7   |
| 4      568  68    | 58   9    7  | 1   3     2   |
+-------------------+--------------+---------------+
| (268)  3    (268) | 78   578  9  | 4   1     56  |
| 7      1    4     | 6    35   2  | 35  9     8   |
| 8(-6)  9    5     | 14   348  13 | 2   7     36  |
+-------------------+--------------+---------------+
| 3      4    (28)  | 9    6    5  | 7   (28)  1   |
| (56)   67   1     | 37   2    8  | 35  4     9   |
| (258)  78   9     | 14   347  13 | 6   (28)  35  |
+-------------------+--------------+---------------+
In order to avoid the unresolvable loop (28)r4c13,r7c38,r9c18 : [6r4c13=5r9c1-(5=6)r8c1]-(6=8)r6c1; stte

Analysis of the puzzle from B6 gives :
Code:
+---------------+-----------------+--------------+
| 1    28   7   | 238   38     6  | 9     5   4  |
| 9    25   3   | 25    1      4  | 8     6   7  |
| 4    568  68  | 58    9      7  | 1     3   2  |
+---------------+-----------------+--------------+
| 268  3    268 | 78    8(57)  9  | 4     1   56 |
| 7    1    4   | 6     3(5)   2  | 3-5   9   8  |
| 68   9    5   | 14    348    13 | 2     7   36 |
+---------------+-----------------+--------------+
| 3    4    28  | 9     6      5  | 7     28  1  |
| 56   67   1   | (37)  2      8  | (35)  4   9  |
| 258  78   9   | 14    34(7)  13 | 6     28  35 |
+---------------+-----------------+--------------+
ALS-Wing[5r8c7=7r8c4-7r9c5=(7-5)r4c5=5r5c5]-(5=3)r5c7; stte of a unique solution
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keith



Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA

PostPosted: Tue Feb 16, 2016 1:39 pm    Post subject: Reply with quote

JC,

There's a remote pair (35) not needed.

There's an X-wing on 3 in C69 that reveals an XY-wing 4-78 that solves it.

Keith
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dongrave



Joined: 06 Mar 2014
Posts: 563

PostPosted: Tue Feb 16, 2016 2:25 pm    Post subject: Reply with quote

Darn x wings! There ought be a law against them.
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keith



Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA

PostPosted: Tue Feb 16, 2016 2:59 pm    Post subject: Reply with quote

dongrave wrote:
Darn x wings! There ought be a law against them.

At least we should admit they're a fish and not a wing.

Keith
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JC Van Hay



Joined: 13 Jun 2010
Posts: 494
Location: Charleroi, Belgium

PostPosted: Tue Feb 16, 2016 3:31 pm    Post subject: Reply with quote

Another (and simpler) optimized solution suggested by the analysis of the puzzle from B6 :

23 singles
Pointing{5B2} -> -5r4c4
HP{1C4, 4C4} -> -(378)r69c4
Code:
+----------------+------------------+------------+
| 1    28    7   | 238   38      6  | 9   5   4  |
| 9    25    3   | 25    1       4  | 8   6   7  |
| 4    568   68  | 58    9       7  | 1   3   2  |
+----------------+------------------+------------+
| 268  3     268 | (78)  58(7)   9  | 4   1   56 |
| 7    1     4   | 6     35      2  | 35  9   8  |
| 68   9     5   | 14    3-8(4)  13 | 2   7   36 |
+----------------+------------------+------------+
| 3    4     28  | 9     6       5  | 7   28  1  |
| 56   567   1   | 37    2       8  | 35  4   9  |
| 258  2578  9   | 14    3(47)   13 | 6   28  35 |
+----------------+------------------+------------+
Wing{4C5, 7C5, (78)r4c4} -> -8r6c5; stte
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