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Free Press Aug 13, 2010

 
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keith



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

PostPosted: Fri Aug 13, 2010 5:13 pm    Post subject: Free Press Aug 13, 2010 Reply with quote

Not yet started:

Code:
Puzzle: FP081310
+-------+-------+-------+
| . . . | . . . | . . . |
| . 2 . | 5 . 8 | . 3 . |
| . 3 . | . 9 . | . . 4 |
+-------+-------+-------+
| 8 . . | 3 . 5 | . 6 2 |
| . . . | 8 . . | . . . |
| 5 7 . | 9 . 4 | . . 8 |
+-------+-------+-------+
| 6 . . | . 5 . | . 7 . |
| . 8 . | 7 . 1 | . 5 . |
| 4 . . | . . . | . . . |
+-------+-------+-------+

Play this puzzle online at the Daily Sudoku site

Keith
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Marty R.



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

PostPosted: Fri Aug 13, 2010 6:52 pm    Post subject: Reply with quote

This grid was pretty messy after populating it with candidates, but it looked worse than it actually was.

Quote:
Coloring (2)
DP in boxes 123 (12-17-27); r1c2=6
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keith



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

PostPosted: Sat Aug 14, 2010 5:20 am    Post subject: Reply with quote

Marty,

An interesting, and unexpected solution.

I found many wings.

By the way, should I bother posting these puzzles any more? It seems like the level of interest is approaching zero.

Keith
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Marty R.



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

PostPosted: Sat Aug 14, 2010 1:36 pm    Post subject: Reply with quote

Quote:
By the way, should I bother posting these puzzles any more? It seems like the level of interest is approaching zero.

Only you can decide. I enjoy them, but I understand if you feel it's not worth it.
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CORUJA



Joined: 16 Jun 2007
Posts: 15
Location: BRUMADINHO - MG; BRAZIL

PostPosted: Sat Aug 14, 2010 2:49 pm    Post subject: Free Press Aug 13, 2010 Reply with quote

Keith,
I like the puzzles you post very much, and learned a lot following the discussion around their solutions. But if you decide to stop posting them, I can only thank you for the many hours of brain stimulating entertainment!![/code]
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tlanglet



Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills

PostPosted: Sat Aug 14, 2010 9:46 pm    Post subject: Reply with quote

Marty R. wrote:
This grid was pretty messy after populating it with candidates, but it looked worse than it actually was.

Quote:
Coloring (2)
DP in boxes 123 (12-17-27); r1c2=6


Marty, that was a really great move with the ADP. I had the same initial step as you, and then noticed your second step but was unable to make any useful conclusion with it. However, after reading your post, I went back to review it and found a contradiction chain that resulted in your result. Cool......... Cool Cool

Ted
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tlanglet



Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills

PostPosted: Sat Aug 14, 2010 9:49 pm    Post subject: Reply with quote

Keith,

I also enjoy your posting of the weekly Free Press and look forward to working it. I have been reducing the number of posts I make but will resume so that you have some indication of interest.

Ted
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tlanglet



Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills

PostPosted: Sat Aug 14, 2010 10:18 pm    Post subject: Reply with quote

Another two step solution is a 6-cell ADP (258)r13c378. The only external box implication to prevent the DP is r1c9=5. However , this does not solve the puzzle; coloring on 2, or several xy-wings complete it.

Ted
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tlanglet



Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills

PostPosted: Sat Aug 14, 2010 10:44 pm    Post subject: Reply with quote

Still another two stepper not involving a DP.


Quote:
Coloring 2
Flightless xy-wing 5-67 vertex (57)r1c9 and pseudocell (56)r5c69 plus transport (6)r2c7-r2c3=(6)r6c3; r6c5<>6

Ted
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ronk



Joined: 07 May 2006
Posts: 398

PostPosted: Sat Aug 14, 2010 11:46 pm    Post subject: Reply with quote

tlanglet wrote:
Another two step solution is a 6-cell ADP (258)r13c378. The only external box implication to prevent the DP is r1c9=5.

Ted, a BUG-Lite of this general layout, i.e., six cells in two rows, needs to have two cells in each of the three boxes. In general, each digit of a BUG-Lite or BUG pattern must appear exactly twice in its respective row, column and box. To apply this rule to a BUG-Lite, only the cells of the BUG-Lite pattern are considered.
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keith



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

PostPosted: Sun Aug 15, 2010 5:20 am    Post subject: Reply with quote

After basics:
Code:
+----------------------+----------------------+----------------------+
| 179    46     58     | 12     3467   367    | 125679 289    1579   |
| 179    2      46     | 5      467    8      | 1679   3      179    |
| 17     3      58     | 12     9      67     | 12567  28     4      |
+----------------------+----------------------+----------------------+
| 8      49     14     | 3      17     5      | 79     6      2      |
| 23     69     1236   | 8      1267   267    | 579    4      579    |
| 5      7      26@    | 9      26@    4      | 3      1      8      |
+----------------------+----------------------+----------------------+
| 6      1      23#    | 4      5      239    | 8      7      39$    |
| 23     8      9      | 7      23#    1      | 4      5      6      |
| 4      5      7      | 6      8      39$    | 129    29     139    |
+----------------------+----------------------+----------------------+
There are a number of moves that clear out the bottom third of the puzzle. One of them is the W-wing 2-3 that solves R8C1 as 2.

However, note that the 23# pincers excite the 39$ pair, clearing out 9 in R9B9 and R7C6.

Leading to here:
Code:
+----------------+----------------+----------------+
| 17   46   8    | 12   467  3    | 2567 9    57   |
| 9    2    46   | 5    467  8    | 67   3    1    |
| 17   3    5    | 12   9    67   | 267  8    4    |
+----------------+----------------+----------------+
| 8    49   14   | 3    17   5    | 79   6    2    |
| 3    69   12   | 8    12   67   | 579  4    57   |
| 5    7    26   | 9    26   4    | 3    1    8    |
+----------------+----------------+----------------+
| 6    1    3    | 4    5    2    | 8    7    9    |
| 2    8    9    | 7    3    1    | 4    5    6    |
| 4    5    7    | 6    8    9    | 1    2    3    |
+----------------+----------------+----------------+
A very obvious swordfish on 7 in C169 leads to a BUG+1.

There are other paths.

Keith
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tlanglet



Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills

PostPosted: Sun Aug 15, 2010 2:59 pm    Post subject: Reply with quote

ronk wrote:
tlanglet wrote:
Another two step solution is a 6-cell ADP (258)r13c378. The only external box implication to prevent the DP is r1c9=5.

Ted, a BUG-Lite of this general layout, i.e., six cells in two rows, needs to have two cells in each of the three boxes. In general, each digit of a BUG-Lite or BUG pattern must appear exactly twice in its respective row, column and box. To apply this rule to a BUG-Lite, only the cells of the BUG-Lite pattern are considered.


Ron, thanks for the info. Looking at the configuration now, it is obvious why the necessity for each digit to appear exactly twice in each row, column and box.

Could you refer me to a thread that discusses these types of issues for various deadly patterns. To date, my searches have not been useful.

Ted
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cgordon



Joined: 04 May 2007
Posts: 769
Location: ontario, canada

PostPosted: Mon Aug 16, 2010 3:56 pm    Post subject: Reply with quote

Nothing fancy - just x-wings and skyscrapers.

Keith: These puzzles are good fillers during those recurring droughts between VH's.

Iactually prefer them to the VH's which are all too often one-step xy wingers.

Craig
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