December 31, 2019

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December 31, 2019

Postby tarek » Tue Dec 31, 2019 10:41 am

Code: Select all
+-------+-------+-------+
| . . 4 | . . . | 7 . . |
| 3 . . | . 9 . | . . 8 |
| . 9 . | . . . | . 5 . |
+-------+-------+-------+
| . . . | 8 . 6 | . . . |
| 2 3 . | . 4 . | . 8 1 |
| . . . | 7 . 2 | . . . |
+-------+-------+-------+
| 8 . . | 3 7 1 | . . 9 |
| 4 . . | 9 . 8 | . . 5 |
| . 1 3 | . . . | 8 7 . |
+-------+-------+-------+
..4...7..3...9...8.9.....5....8.6...23..4..81...7.2...8..371..94..9.8..5.13...87.


Apologies but this one apears to be more difficult than the planned scope of the daily sudoku by a notch or 2
ER=7.3 with a few forcing chains
If I'm still posting these puzzles after this batch of puzzles finish then I'll select them more carefully.

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Re: December 31, 2019

Postby eleven » Tue Dec 31, 2019 4:11 pm

2 steps.
Code: Select all
+-------------------+--------------------+-------------------+
| 16    268   4     | 126   d2568 c35    | 7     9    b236   |
| 3     256   1256  | 1246   9     7     | 124   146   8     |
| 7     9     1268  | 1246 d#26+8  34    | 1234  5   a#26+34 |
+-------------------+--------------------+-------------------+
| 15    4     19    | 8      3     6     | 59    2     7     |
| 2     3     7     | 5      4     9     | 6     8     1     |
| 56    68    689   | 7      1     2     | 59    34   a34    |
+-------------------+--------------------+-------------------+
| 8    #256  #256   | 3      7     1     |#24   #46    9     |
| 4     7    #26    | 9     #26    8     | 13    13    5     |
| 9     1     3     | 246    256   45    | 8     7    #26    |
+-------------------+--------------------+-------------------+

7-link oddagon 26 in #-marked cells, guardians 8r3c5, 34r3c9
34r36c9 - 3r1c9 = (3-5)r1c6 = 58r13c5
=> 8r3c5, solves with (grouped) skyscraper 2.

HNY to all.

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Re: December 31, 2019

Postby Cenoman » Wed Jan 01, 2020 10:32 pm

Can't compete with eleven's solution !
Here is a slight variation:
I had the following two "parallel" krakens (plus the skyscraper) and wondered how to merge them into one step.
Hidden Text: Show
Kraken (2)r139c9
(2-3)r1c9 = (358)b2p238
(2)r3c9
(2)r9c9 - r9c45 = (2)r8c5
=>-2r3c5

Kraken (6)r139c9
(6-3)r1c9 = (358)b2p238
(6)r3c9
(6)r9c9 - r9c45 = (6)r8c5
=>-6r3c5

The result:
Code: Select all
 +--------------------+---------------------+----------------------+
 |  16   268   4      |  126   b2568  b35   |  7      9    a236    |
 |  3    256   1256   |  1246   9      7    |  124    146   8      |
 |  7    9     1268   |  1246  b8-26   34   |  1234   5    A2346X  |
 +--------------------+---------------------+----------------------+
 |  15   4     19     |  8      3      6    |  59     2     7      |
 |  2    3     7      |  5      4      9    |  6      8     1      |
 |  56   68    689    |  7      1      2    |  59     34    34     |
 +--------------------+---------------------+----------------------+
 |  8    256   256    |  3      7      1    |  24     46    9      |
 |  4    7     26     |  9     Z26C    8    |  13     13    5      |
 |  9    1     3      | Y246B  Y256B   45   |  8      7    X26A    |
 +--------------------+---------------------+----------------------+

1. Almost hidden pair (26)r39c9, considering each of its two configurations:
(2|6-3)r1c9 = (358)b2p238
(2)r3c9^ & (6)r9c9 - r9c45 = (6)r8c5
(6)r3c9^ & (2)r9c9 - r9c45 = (2)r8c5
=> -26 r3c5; 11 placements and basics

2. Skyscraper (2)r1c5 = r1c9 - r9c9 = r9c45 => -2 r8c5; ste
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