The New Sudoku Players' Forum

[yzfwsf]

My solver use the same technique for 7 consecutive steps.

Code: Select all

8.......1..51372...7...8.4.6...8......9..27...5.......5....4....9.3...8...7.9...6

from this point ,can you find the 7 steps?

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.--------------.-----------------.--------------------.
| 8   23   23  | 4569  456   69  | 56     7     1     |
| 4   6    5   | 1     3     7   | 2      9     8     |
| 9   7    1   | 256   256   8   | 356    4     35    |
:--------------+-----------------+--------------------:
| 6   123  234 | 7     8     39  | 13459  135   23459 |
| 13  8    9   | 456   1456  2   | 7      16    34    |
| 7   5    234 | 469   146   369 | 8      136   2349  |
:--------------+-----------------+--------------------:
| 5   13   8   | 26    267   4   | 19     23    79    |
| 12  9    6   | 3     27    15  | 145    8     457   |
| 23  4    7   | 8     9     15  | 135    1235  6     |
'--------------'-----------------'--------------------'

[SteveG48]

Code: Select all

 *--------------------------------------------------------------------*
 | 8      23     23     | 4569   456    69     | 56     7      1      |
 | 4      6      5      | 1      3      7      | 2      9      8      |
 | 9      7      1      | 256    256    8      | 356    4      35     |
 *----------------------+----------------------+----------------------|
 | 6     d123    234    | 7      8      39     |c13459 c135    23459  |
 | 3-1    8      9      |a456   a1456   2      | 7     a16    a34     |
 | 7      5      234    | 469    146    369    | 8     b136    2349   |
 *----------------------+----------------------+----------------------|
 | 5      13     8      | 26     267    4      | 19     23     79     |
 | 12     9      6      | 3      27     15     | 145    8      457    |
 | 23     4      7      | 8      9      15     | 135    1235   6      |
 *--------------------------------------------------------------------*


(1=4563)r5c4589 - (3|6=1)r6c8 - r4c78 = 1r4c1 => -1 r5c1 ; stte

(Couldn't resist. Now I'll start looking for the 7 steps. )

[Leren]

I think it's UR's. So far I have :

1. Hidden Type 1 (27) r78c59 => - 2 r7c9

2. Hidden Type 2 (23) r14c23 => - 3 r4c3

3. Hidden Type 4 (16) r56c58 => - 6 r6c5

4. Hidden Type 4 (26) r37c45 => - 6 r3c4

5. Hidden Type 6 (69) r16c46 => - 6 r1c4

Some intervening moves:

6. Hidden Type 1 (24) r46c39 => - 4 r46c9

Some intervening moves:

7. Hidden Type 5 (16) r56c58 => - 6 r5c5

If I can improve on this I'll edit this post.

Leren

[SteveG48]

I've been tracking URs as well, hidden and unique, but I need to take singles along the way. My sequence:

-6 r6c5 (HR r56c58)
-2 r3c5 (r37c45)
-3 r4c3 (r14c23)
-4 r6c9 (HR r46c39)
-6 r5c5 (r15c45)
-6 r1c5 (r13c57)
-45 r5c5 (r15c45)

Subject to checking!

[Mauriès Robert]

Hi all,
I am one of those who consider UR not to be a logical reasoning for solving a puzzle, because it is based on the sole affirmation of uniqueness of the author of the puzzle who can make a mistake. A debate which is not new on this forum and which I do not want to relaunch.
Having said that, the identification of a UR is a useful indication for building a chain of elimination. For example with the set 23r14c23 (which could be a UR) suggests the chain (-4r4c3)->4r4c6->2r6c9->9r4c79->3r4c6 => -3r4c3, this without the need to use uniqueness.
But if we accept UR as the reasoning (and therefore the uniqueness of the solution), I don't see why the UR model should be used 7 times to solve this puzzle, when one time is enough, like this :
The set 26r37c45 suggests the chain (-7r7c5)->26r7c45->3r7c8->1r7c2->1r5c1->3r5c9->5r3c9->UR(26r37c45) => r7c5=7, stte.
Cordialy
Robert

[yzfwsf]

This puzzle is just for fun, not to explain how to solve it. In fact, my solver does not need to use UR. From the PM is provided, stte can be realized in one step.
Grouped Almost Locked Set W-Wing: A=r59c1-{123}, B=r567c8-{1236}, connect by 1r4 => r9c8<>2;stte

Hidden Text: Show

7 steps UR

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Uniqueness Test 7: 24 in r4c39,r6c39; 3*conjugate pairs(2r6,4c3,2c9) => r6c9 <> 4
Hidden Rectangle: 16 in r5c58,r6c58 => r6c5 <> 6
Uniqueness Test 7: 16 in r5c58,r6c58; 1*biCell + 2*conjugate pairs(6c8,1r6) => r5c5 <> 6
Uniqueness Test 7: 23 in r1c23,r4c23; 2*biCell + 1*conjugate pairs(2c2) => r4c3 <> 3
Uniqueness Test 7: 24 in r4c39,r6c39; 1*biCell + 2*conjugate pairs(4c3,2r6) => r4c9 <> 4
Uniqueness Test 7: 26 in r3c45,r7c45; 1*biCell + 2*conjugate pairs(6r7,2r3) => r3c4 <> 6
Uniqueness Test 7: 69 in r1c46,r6c46; 1*biCell + 2*conjugate pairs(6c6,9c4) => r1c4 <> 6

[Mauriès Robert]

Hi yzfwsf,

This puzzle is just for fun, not to explain how to solve it.

Yes, I had understood that it was a curiosity and not the best resolution.
The aim of my talk is to show that only one use of UR is possible here, but that more generally, if we do not accept the UR rule, we can still use this configuration without using uniqueness.
Cordially
Robert