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Challenging Puzzle 072518

 
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immpy



Joined: 06 May 2017
Posts: 570

PostPosted: Wed Jul 25, 2018 11:10 pm    Post subject: Challenging Puzzle 072518 Reply with quote

Enjoy the puzzle...

Code:

+-------+-------+-------+
| . 2 . | 1 . 7 | . 9 . |
| . 3 . | . . . | . 1 . |
| . . 7 | . 9 . | 2 . . |
+-------+-------+-------+
| . 5 4 | . . 1 | . . . |
| . . . | 2 8 4 | . . . |
| . . . | 3 . . | 8 4 . |
+-------+-------+-------+
| . . 5 | . 4 . | 7 . . |
| . 8 . | . . . | . 2 . |
| . 1 . | 7 . 9 | . 8 . |
+-------+-------+-------+

Play this puzzle online at the Daily Sudoku site

cheers...immp
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dongrave



Joined: 06 Mar 2014
Posts: 563

PostPosted: Wed Jul 25, 2018 11:13 pm    Post subject: Reply with quote

Thanks immpy! I can't get the puzzle from Helmut's site tonight! (I kept getting an error about 'resource limit exceeded'.) Now I've got one to do.
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immpy



Joined: 06 May 2017
Posts: 570

PostPosted: Wed Jul 25, 2018 11:17 pm    Post subject: Reply with quote

You are welcome dongrave. This is a tough one. Enjoy.
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immpy



Joined: 06 May 2017
Posts: 570

PostPosted: Thu Jul 26, 2018 10:33 pm    Post subject: Reply with quote

Here is the grid after basics:

Code:

+-------------+-------------+--------------+
| 56  2   68  | 1  356 7    | 4   9   3568 |
| 569 3   689 | 4  2   568  | 56  1   7    |
| 1   4   7   | 56 9   3568 | 2   356 3568 |
+-------------+-------------+--------------+
| 8   5   4   | 9  67  1    | 36  367 2    |
| 369 679 369 | 2  8   4    | 1   567 569  |
| 2   679 1   | 3  567 56   | 8   4   69   |
+-------------+-------------+--------------+
| 369 69  5   | 8  4   2    | 7   36  1    |
| 7   8   36  | 56 1   356  | 9   2   4    |
| 4   1   2   | 7  36  9    | 356 8   356  |
+-------------+-------------+--------------+

Play this puzzle online at the Daily Sudoku site

There is an early W-Wing 6/5 in r3c4, r6c6 connected by 5 in r8c46=>r23c6<>6. That brings us here:

Code:

+-------------+------------+--------------+
| 56  2   68  | 1  356 7   | 4   9   3568 |
| 569 3   689 | 4  2   58  | 56  1   7    |
| 1   4   7   | 56 9   358 | 2   356 3568 |
+-------------+------------+--------------+
| 8   5   4   | 9  67  1   | 36  367 2    |
| 369 679 369 | 2  8   4   | 1   567 569  |
| 2   679 1   | 3  567 56  | 8   4   69   |
+-------------+------------+--------------+
| 369 69  5   | 8  4   2   | 7   36  1    |
| 7   8   36  | 56 1   356 | 9   2   4    |
| 4   1   2   | 7  36  9   | 356 8   356  |
+-------------+------------+--------------+

Play this puzzle online at the Daily Sudoku site

The program I used to create this puzzle suggests that a Finned Franken Squirmbag (lol...of all things, right) exists on 6 at this stage. Like I would be able to find and/or identify it...lol. I am thinking strong links on the 5s could be used to make some useful eliminations, but I instead opted for a Finned XY-Wing of 356 with the pivot at r8c6, and pincers at r6c6 and r9c5. The pivot contains the extra candidate or fin (in this case a 6). Assuming the XY-Wing is true results in a contradiction after making would-be eliminations. Therefore, the fin of 6 is indeed true for r8c6. This will take the puzzle to its conclusion. In fact, the earlier W-Wing could have been bypassed if one chose to use the Finned XY-Wing initially.


Last edited by immpy on Thu Jul 26, 2018 11:05 pm; edited 1 time in total
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immpy



Joined: 06 May 2017
Posts: 570

PostPosted: Thu Jul 26, 2018 11:00 pm    Post subject: Reply with quote

One last thing...if one is indeed skilled and capable enough with Finned Franken Squirmbags, the elimination that results from that would be r6c9<>6(=9!). There would still be some more work to do. Another W-Wing and a pair of Skyscrapers await for the solving if one follows this route.

cheers all...immp
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Clement



Joined: 24 Apr 2006
Posts: 1110
Location: Dar es Salaam Tanzania

PostPosted: Thu Aug 02, 2018 5:39 pm    Post subject: Challenging Puzzle 072518 Reply with quote

I have to settle with two AICs
Code:

+----------------------+----------------------+----------------------+
| e56      2       68  | 1      d356     7    | 4       9       3568 |
| f569     3       689 | 4       2       568  | g56     1       7    |
| 1        4       7   | 56      9       3568 | 2       356     3568 |
+----------------------+----------------------+----------------------+
| 8        5       4   | 9      d67      1    | 36     c367     2    |
| 369      679     369 | 2       8       4    | 1      b567    a569  |
| 2        679     1   | 3       567     56   | 8       4       69   |
+----------------------+----------------------+----------------------+
| 369      69      5   | 8       4       2    | 7       36      1    |
| 7        8       36  | 56      1       356  | 9       2       4    |
| 4        1       2   | 7      d36      9    | h356    8       36-5 |
+----------------------+----------------------+----------------------+

1): (5)r5c9 = (5-7)r5c8 = r4c8 - (7=5)r149c5 - r1c1 = r2c1 - r2c7 = (5)r9c7 => - 5r9c9
Opens the following grid
Code:

+---------------------+----------------------+-------------------+
| 56      2       68  | 1      c35      7    | 4     9       358 |
| 59      3       89  | 4       2       58   | 6     1       7   |
| 1       4       7   | 56      9      b3568 | 2    a35      358 |
+---------------------+----------------------+-------------------+
| 8       5       4   | 9       67      1    | 3     67      2   |
| 369    f679     369 | 2       8       4    | 1    g67-5    569 |
| 2      e679     1   | 3      d567     56   | 8     4       69  |
+---------------------+----------------------+-------------------+
| 369     69      5   | 8       4       2    | 7     36      1   |
| 7       8       36  | 56      1       356  | 9     2       4   |
| 4       1       2   | 7       36      9    | 5     8       36  |
+---------------------+----------------------+-------------------+

2): (5=3)r3c8 - r3c6 = (3-5)r1c5 = (5-7)r6c5 = r6c2 - r5c2 = (7)r5c8 => - 5r5c8; stte
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Ajò Dimonios



Joined: 01 May 2017
Posts: 339
Location: Sassari Italy

PostPosted: Thu Aug 02, 2018 9:23 pm    Post subject: Reply with quote

Hi everyone
Code:

+-------------+-------------+--------------+
| 56  2   68  | 1  356 7    | 4   9   3568 |
| 569 3   689 | 4  2   568  | 56  1   7    |
| 1   4   7   | 56 9   3568 | 2   356 3568 |
+-------------+-------------+--------------+
| 8   5   4   | 9  67  1    | 36  367 2    |
| 369 679 369 | 2  8   4    | 1   567 569  |
| 2   679 1   | 3  567 56   | 8   4   69   |
+-------------+-------------+--------------+
| 369 69  5   | 8  4   2    | 7   36  1    |
| 7   8   36  | 56 1   356  | 9   2   4    |
| 4   1   2   | 7  36  9    | 356 8   356  |
+-------------+-------------+--------------+

Play this puzzle online at the Daily Sudoku site

(5-67)R5C8=(7-63)R4C8=(3-6)R4C7=6R4C5-6R9C5=6R9C79-6R7C8=6R3C8-6R3C4 and (5-7)R5C8=7R4C8-7R4C5=(7-5)R6C5=5R1C5-5R3C4=>R3C4=Ø=>-5R5C8=>solution in one step.

Ciao a tutti Paolo
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