March 22, 2020

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March 22, 2020

Postby tarek » Sun Mar 22, 2020 11:44 am

Code: Select all
+-------+-------+-------+
| . 7 . | . . 9 | . . . |
| 3 9 . | 5 . . | 6 . 8 |
| . . . | . . . | . . 9 |
+-------+-------+-------+
| . 3 . | 9 8 . | 7 . . |
| . . . | 2 . . | . . . |
| 2 . . | . . . | . 1 . |
+-------+-------+-------+
| . 1 . | 8 . . | . 2 . |
| . . . | . . 4 | 1 . 3 |
| . 8 5 | . . . | . 4 . |
+-------+-------+-------+
.7...9...39.5..6.8........9.3.98.7.....2.....2......1..1.8...2......41.3.85....4.

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Re: March 22, 2020

Postby SteveG48 » Sun Mar 22, 2020 3:33 pm

Code: Select all
 *-----------------------------------------------------------*
 | 568   7     268   | 36    236   9     | 4     35    1     |
 | 3     9    c12    | 5     4   ad12    | 6     7     8     |
 | 56    4    c16    | 1367  1367  8     | 2     35    9     |
 *-------------------+-------------------+-------------------|
 | 1     3     4     | 9     8     5     | 7     6     2     |
 | 78    5     78    | 2     16    6-1   | 3     9     4     |
 | 2     6     9     | 4     37   a37    | 8     1     5     |
 *-------------------+-------------------+-------------------|
 | 4     1     3     | 8     9    a67    | 5     2     67    |
 | 9     2    c67    |b67    5     4     | 1     8     3     |
 | 67    8     5     | 13    123  a123   | 9     4     67    |
 *-----------------------------------------------------------*


(1=2376)r2679c6 - 6r8c4 = (612)r238c3 - (2=1)r2c6 => -1 r5c6 ; stte
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Re: March 22, 2020

Postby Cenoman » Sun Mar 22, 2020 3:56 pm

Failed solution deleted.
Last edited by Cenoman on Sun Mar 22, 2020 9:46 pm, edited 1 time in total.
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Re: March 22, 2020

Postby SteveG48 » Sun Mar 22, 2020 6:16 pm

Cenoman wrote:
Code: Select all
 +-------------------+----------------------+-----------------+
 |  568*  7    268*  | c36#   b236#   9     |  4    35   1    |
 |  3     9   g12    |  5      4     h12    |  6    7    8    |
 |  56    4   f16    |  1367   367-1  8     |  2    35   9    |
 +-------------------+----------------------+-----------------+
 |  1     3    4     |  9      8      5     |  7    6    2    |
 |  78*   5    78*   |  2     a16     6-1   |  3    9    4    |
 |  2     6    9     |  4      37     37    |  8    1    5    |
 +-------------------+----------------------+-----------------+
 |  4     1    3     |  8      9      67*   |  5    2    67*  |
 |  9     2   e67*   | d67*    5      4     |  1    8    3    |
 |  67*   8    5     |  13     123    123   |  9    4    67*  |
 +-------------------+----------------------+-----------------+

DP(678)r15c13, r789c13469 using externals
(1=6)r5c5 - r1c5 == r1c4 - r8c4 = r8c3 - (6=1)r3c3 - r2c3 = (1)r2c6 => -1r5c6, r3c5; ste


Cenoman, I love the idea, but I don't see the DP. If the 6,7 cells in box 8 were in the same column, then I would, but they're not. As it is, you've used the DP to declare 6r1c5==6r1c4, but when we solve the puzzle we see that neither of those cells is a 6.
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Re: March 22, 2020

Postby eleven » Sun Mar 22, 2020 9:34 pm

Yes, either the 6 or 7 in r13c4 fixes the pattern to one solution.
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Re: March 22, 2020

Postby Cenoman » Sun Mar 22, 2020 9:45 pm

SteveG48 wrote:
Cenoman, I love the idea, but I don't see the DP. If the 6,7 cells in box 8 were in the same column, then I would, but they're not. As it is, you've used the DP to declare 6r1c5==6r1c4, but when we solve the puzzle we see that neither of those cells is a 6.


Yes, Steve ! The Covid19 confinement provides me time enough to get the details right for sudoku solutions, though.
I guessed I had checked all the footprints of the DP pattern, but obviously, I forgot to check columns 46... The devil is in the detail.
Shame on me, I will be tarred and feathered :cry:

PS failed solution deleted.
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Re: March 22, 2020

Postby pjb » Sun Mar 22, 2020 10:19 pm

Code: Select all
 568     7       268    | 36     236    9      | 4      35     1     
 3       9      b12     | 5      4     c12     | 6      7      8     
 56      4      a16     | 137-6  1367   8      | 2      35     9     
------------------------+----------------------+---------------------
 1       3       4      | 9      8      5      | 7      6      2     
 78      5       78     | 2      16    d16     | 3      9      4     
 2       6       9      | 4      37     37     | 8      1      5     
------------------------+----------------------+---------------------
 4       1       3      | 8      9     e67     | 5      2      67     
 9       2       7-6    |f67     5      4      | 1      8      3     
 67      8       5      | 13     123    123    | 9      4      67     

XY chain:
(6=1)r3c3 - (1=2)r2c3 - (2=1)r2c6 - (1=6)r5c6 - (6=7)r7c6 - (7=6)r8c4 => -6 r3c4, r8c3; stte

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