January 12, 2020

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January 12, 2020

Postby tarek » Sun Jan 12, 2020 9:14 am

Code: Select all
+-------+-------+-------+
| . . . | . . . | . . . |
| . . 8 | . . 7 | . 1 6 |
| . 1 3 | 5 6 . | . . . |
+-------+-------+-------+
| . . 2 | 4 5 . | 1 . 7 |
| . . 4 | 7 . . | . 3 . |
| . 6 . | . . . | . . . |
+-------+-------+-------+
| . . . | 3 . . | . . 8 |
| . 5 . | . 1 . | . . 4 |
| . 2 . | 8 . . | 7 5 . |
+-------+-------+-------+
...........8..7.16.1356......245.1.7..47...3..6..........3....8.5..1...4.2.8..75.


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Re: January 12, 2020

Postby Mauriès Robert » Sun Jan 12, 2020 5:59 pm

Hi all,
A two-step resolution with TDP.

Step 1 with an anti-track :
P'(2r56c9) : -2r56c9->2r3c9-> --- ->2r6c4 and 6r5c7 (see puzzle) => -2c78b6 => r3c9=9

puzzle1: Show
Image

Step 2 with two conjugated tracks :
P(8r4c6) : 8r4c6->6r5c6->1r6c4
P(8r4c8) : 8r4c8-> --- ->1r6c4 (see puzzle2) => r6c4=1, stte

puzzle2: Show
Image

Robert
Last edited by Mauriès Robert on Mon Jan 13, 2020 8:28 am, edited 1 time in total.
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Re: January 12, 2020

Postby Cenoman » Sun Jan 12, 2020 8:20 pm

The most reasonable solution (to me) is in two steps
Code: Select all
 +------------------+----------------------+----------------------+
 |  6     7   c59   |  129   2489   1489   | b24589   248   3     |
 |  245  c49   8    |  29    3      7      | a259-4   1     6     |
 |  24    1    3    |  5     6      489    |  2489    7     29    |
 +------------------+----------------------+----------------------+
 |  9     3    2    |  4     5      68     |  1       68    7     |
 |  15    8    4    |  7     29     169    |  269     3     259   |
 |  7     6    15   |  129   289    3      |  2489    248   259   |
 +------------------+----------------------+----------------------+
 |  14    49   19   |  3     7      5      |  26      26    8     |
 |  8     5    7    |  6     1      2      |  3       9     4     |
 |  3     2    6    |  8     49     49     |  7       5     1     |
 +------------------+----------------------+----------------------+

1. H-wing (5)r2c7 = r1c7 - (5=94)b1p35 => -4 r2c7; two placements & basics
Code: Select all
 +-----------------+----------------------+--------------------+
 |  6    7    59   |  129   2489   1489   |  2458   248   3    |
 | c45  c49   8    | c29    3      7      |  25     1     6    |
 |  2    1    3    |  5     6      48     |  48     7     9    |
 +-----------------+----------------------+--------------------+
 |  9    3    2    |  4     5      68     |  1      68    7    |
 | d15   8    4    |  7     29    a69-1*  | a69*    3     25   |
 |  7    6    15   |ba129*  289    3      | a489*   48    25   |
 +-----------------+----------------------+--------------------+
 |  14   49   19   |  3     7      5      |  26     26    8    |
 |  8    5    7    |  6     1      2      |  3      9     4    |
 |  3    2    6    |  8     49     49     |  7      5     1    |
 +-----------------+----------------------+--------------------+

2. Almost M3-wing [(6)r5c6 = (6-9)r5c7 = r6c7 - (9=1)r6c4] = (2)r6c4 - (2=495)r2c124 - (5=1)r5c1 => -1 r5c6; ste

But a one-stepper exists, with a 5-cell kraken in the 2s
Hidden Text: Show
Kraken row (2)r6c45789
(2)r6c4 - (2=9)r2c4 - (9=245)b1p457
(2)r6c5 - (2=91)b5p57 - r6c3 = (1-5)r5c1 = (5)r2c1
(2)r6c7 - (2=6)r7c7 - r5c7 = (6-1)r5c6 = (1-5)r5c1 = (5)r2c1
(2)r6c8 - r56c9 = r3c9 - (2=4)r3c1 - r2c12 = (4)r2c7
(2-5)r6c9 = r5c9 - r5c1 = (5)r2c1
=>-5r2c7; ste
Cenoman
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Re: January 12, 2020

Postby eleven » Sun Jan 12, 2020 9:43 pm

Cenoman wrote:The most reasonable solution (to me) is in two steps

Agreed. I cannot look for a one-stepper chain here without always stumbling across the xy-wing.
Then e.g.:
Code: Select all
+-------------------+-------------------+-------------------+
| 6     7     59    | 129   2489  1489  | 2458  248   3     |
|c45   c49    8     |c29    3     7     | 245   1     6     |
| 2     1     3     | 5     6     48    | 48    7     9     |
+-------------------+-------------------+-------------------+
| 9     3     2     | 4     5     68    | 1     68    7     |
|d15    8     4     | 7    a29   a169   |a269   3    e25    |
| 7     6     15    |b129   289   3     | 2489  248   25    |
+-------------------+-------------------+-------------------+
| 14    49    19    | 3     7     5     | 26    26    8     |
| 8     5     7     | 6     1     2     | 3     9     4     |
| 3     2     6     | 8     49    49    | 7     5     1     |
+-------------------+-------------------+-------------------+

(2=619)r5c765 - (1|9=2)r6c4 - (2=495)r2c241 - r5c1 = 5r5c9 => -2r5c9, stte
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Re: January 12, 2020

Postby Leren » Sun Jan 12, 2020 10:12 pm

Similar to eleven. XY Wing followed by a Kraken cell/ Death Blossom :

Code: Select all
*------------------------------------------------*
| 6      7   59 | 129   2489 1489 | 2458 248 3   |
|b45    b49  8  |b29    3    7    | 25   1   6   |
| 2      1   3  | 5     6    48   | 48   7   9   |
|---------------+-----------------+--------------|
| 9      3   2  | 4     5    68   | 1    68  7   |
|c1-5cC  8   4  | 7     29B  169  | 69   3   25B |
| 7      6  b15 |a129aA 289  3    | 489  48  25  |
|---------------+-----------------+--------------|
| 14     49  19 | 3     7    5    | 26   26  8   |
| 8      5   7  | 6     1    2    | 3    9   4   |
| 3      2   6  | 8     49   49   | 7    5   1   |
*------------------------------------------------*

1 r6c4 = (1=5) r6c3   - 5 r5c1;

2 r6c4 - (2=5) r2c124 - 5 r5c1;

9 r6c4 - (9=5) r5c59  - 5 r5c1; -=> - 5 r5c1; stte

Leren
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Re: January 12, 2020

Postby pjb » Mon Jan 13, 2020 2:07 am

Code: Select all
 6       7      c59     | 129    2489   1489   | 24589  248    3     
f245    d49      8      |e29     3      7      | 2459   1      6     
g24      1       3      | 5      6      489    | 2489   7     h29     
------------------------+----------------------+---------------------
 9       3       2      | 4      5      68     | 1      68     7     
a15      8       4      | 7     j29     69-1   | 269    3     i259   
 7       6      b5-1    |k129    289    3      | 2489   248    259   
------------------------+----------------------+---------------------
 14      49      19     | 3      7      5      | 26     26     8     
 8       5       7      | 6      1      2      | 3      9      4     
 3       2       6      | 8      49     49     | 7      5      1     

(1=5*)r5c1 - r6c3 = (5^-9)r1c3 = r2c2 - (9=2#)r2c4 - (25^=4)r2c1 - (4=2)r3c1 - (2=9)r3c9 - (5*9=2)r5c9 - (2=9)r5c5 - (2#9=1)r6c4 => -1 r5c6, r6c3; stte

Phil
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Re: January 12, 2020

Postby Mauriès Robert » Mon Jan 13, 2020 8:56 am

Hi Phil,
pjb wrote:(1=5*)r5c1 - r6c3 = (5^-9)r1c3 = r2c2 - (9=2#)r2c4 - (25^=4)r2c1 - (4=2)r3c1 - (2=9)r3c9 - (5*9=2)r5c9 - (2=9)r5c5 - (2#9=1)r6c4 => -1 r5c6, r6c3; stte

What criterion determines your choice of the 15r5c1 pair to write such a complex string?

Sincerely
Robert
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Re: January 12, 2020

Postby pjb » Mon Jan 13, 2020 10:30 pm

Hi Robert

None really. I determine which digit eliminations yield an stte finish, then generate chains systematically looking for one that gives the desired elimination. In puzzles far too hard for hand solving such as this, I see this as an reasonable approach.

Phil
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Re: January 12, 2020

Postby Mauriès Robert » Tue Feb 04, 2020 5:12 pm

pjb wrote:Hi Robert

None really. I determine which digit eliminations yield an stte finish, then generate chains systematically looking for one that gives the desired elimination. In puzzles far too hard for hand solving such as this, I see this as an reasonable approach.

Phil


Thank you, Phil. :D
Robert
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