The New Sudoku Players' Forum

[rjamil]

Hi,

Look into following one of the Ruud 50K Specialty puzzle:

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4.97...3.1....24....7.......91..5...6...3...5...6..84.......7....32....6.5...93.8

After a hidden single, a box-line reduction intersection removal and a pointing and claiming intersection removal moves (by my solver and one hidden single and two pointing and claiming intersection removal moves by SudokuWiki Sudoku Solver), got (same) following state:

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+---------------+---------------------+-------------------+
| 4    268  9   | 7      1568   168   | 1256  3     12    |
| 1    368  568 | 3589   5689   2     | 4     56789 79    |
| 2358 2368 7   | 134589 145689 13468 | 12569 15689 129   |
+---------------+---------------------+-------------------+
| 2378 9    1   | 48     2478   5     | 26    67    237   |
| 6    2478 248 | 189    3      178   | 129   179   5     |
| 2357 237  25  | 6      1279   17    | 8     4     12379 |
+---------------+---------------------+-------------------+
| 289  1268 268 | 1358   1568   1368  | 7     1259  4     |
| 789  1478 3   | 2      14578  1478  | 159   159   6     |
| 27   5    246 | 14     1467   9     | 3     12    8     |
+---------------+---------------------+-------------------+

Checked next move on Andrew Stuart's SudokuWiki Sudoku Solver that suggest as follows:

WXYZ-Wing2.png (20.39 KiB) Viewed 1294 times

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WXYZ Wing
The four cells {D4,E6,J4,F6} contain in total 1/4/7/8.
 Candidate 1 determines the 'wing' cells (in yellow) and one or other of those 1s must be true. Therefore...
 1 can be taken off E4
 1 can be taken off G6
 1 can be taken off H6

My first question is that, is WXYZ-Wings (or BarnS=4) Apex cell contain only two clues?

Whereas, my solver suggest next move as follows:

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Found WXYZ-Wings Type 3 Cells 68 75 41 50 Clues 1478 remove Clue 1 from Cells 59 77

After that, next move might contain an XY-Wings Transport (either ERI or Line) Ring move.

R. Jamil

[eleven]

Well, i neither understand nor am interested in your question.
Andrew's eliminations are simple to understand (either r4c4=4 and r9c4=1 or r4c4=8 and r56c6=17), so this can't be your problem.
But i am totally lost, what cells your solver means with 68 75 41 50 59 77. Can you translate that into a row/column numbering ?

[rjamil]

Hi eleven,

But i am totally lost, what cells your solver means with 68 75 41 50 59 77. Can you translate that into a row/column numbering ?

Well, I enumerate my grid as 0 to 80 from top-left to bottom-right cell positions. Hope that it will help to translate into row/column numbering.

As far as my question is concern, I have an impression that, for WXYZ-Wings, apex cell should contain at least three or maximum four clues; first wing that shares apex unit should contain two clues and apex and first wing should contain four clues in total; and remaining two wings that share apex unit but not first one wing unit, should contain at least two or maximum three clues each, should contain three clues in total and apex and remaining two wings should contain four clues in total. (Also, rest restrictions are as per normal criteria).

R. Jamil

[StrmCkr]

They can contain as few as 1 (albeit its a single degeneration but still applicable)

[rjamil]

Hi StrmCkr,

Thanks for providing clear picture. (However, I am not that much expert to check any advance strategy before applying basic moves.)

One more question from same puzzle state. Since clue 7 to be placed on one of the E6 and F6 cells only, therefore, it should also be excluded from both box 5 and column 6 other cells? Similarly, since clues 4 and 8 to be placed within column 4 and box 5 respectively, therefore, both should also be excluded from their respective unit other cells?

R. Jamil

[StrmCkr]

Code: Select all

+---------------+---------------------+-------------------+
| 4    268  9   | 7      1568   168   | 1256  3     12    |
| 1    368  568 | 3589   5689   2     | 4     56789 79    |
| 2358 2368 7   | 134589 145689 13468 | 12569 15689 129   |
+---------------+---------------------+-------------------+
| 2378 9    1   | 48     2478   5     | 26    67    237   |
| 6    2478 248 | 189    3      178   | 129   179   5     |
| 2357 237  25  | 6      1279   17    | 8     4     12379 |
+---------------+---------------------+-------------------+
| 289  1268 268 | 1358   1568   1368  | 7     1259  4     |
| 789  1478 3   | 2      14578  1478  | 159   159   6     |
| 27   5    246 | 14     1467   9     | 3     12    8     |
+---------------+---------------------+-------------------+

Almost Locked Set XZ-Rule: A=r9c4 {14}, B=r4c4,r56c6 {1478}, X=4, Z=1 => r5c4,r78c6<>1
Almost Locked Set XZ-Rule: A=r49c4 {148}, B=r56c6 {178}, X=8, Z=1 => r5c4,r78c6<>1
Almost Locked Set XZ-Rule: A=r9c4 {14}, B=r568c6 {1478}, X=4, Z=1 => r7c6<>1

{all of these are wxyz wings, barn size 4}

to answer the question no, none of those eliminations you asked about are applicable from the wing.

its 2 separate almost sets sharing 1 common digit {digit "8" digit to being in set a or set b}

which means any candidate in both sets will always be solved in any of sets a& b cells {that restricted common is digit "1" only, thus any cell that can see all digit "1" cells in both sets a& B can be excluded} other wise there isn't enough candidates in those cells to successfully solve all of them. { try placing digit "1" in any of the elimination cells and at least 1 of the cells in set a or b will be lacking a solution}

[eleven]

But i am totally lost, what cells your solver means with 68 75 41 50 59 77. Can you translate that into a row/column numbering ?

Well, I enumerate my grid as 0 to 80 from top-left to bottom-right cell positions. Hope that it will help to translate into row/column numbering.

I had tried also that without getting any sense out of it. 41 then is r4c6, which is a 5, 77 r9c6, which is a 9. So explain, please.

[StrmCkr]

I had tried also that without getting any sense out of it. 41 then is r4c6, which is a 5, 77 r9c6, which is a 9. So explain, please.

grid by cells left to right and top down

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0 1 2 3 4 5 6 7 8
9 10 11 12 13 14 15 16 17
18 19 20 21 22 23 24 25 26
----------------------------------
27 28 29 30 31 32 33 34 35
36 37 38 39 40 41 42 43 44
45 46 47 48 49 50 51 52 53
-------------------------------
54 55 56 57 58 59 60 61 62
63 64 65 66 67 68 69 70 71
72 73 74 75 76 77 78 79 80

your off by full row:
if u shift it down another 9 you get R5C6

hope that helps

used cells : 68 75 41 50 eliminates from cells 59 77 {he doesn't ignore cells that are already solved on the eliminations}

Almost Locked Set XZ-Rule: A=r9c4 {14}, B=r568c6 {1478}, X=4, Z=1 => r7c6<>1
{which is this one}

[eleven]

I'll never read a post by rjamil again.

[rjamil]

Hi,

Wish to inform that I managed to extend my existing WXYZ-Wings strategy in order to catch any number of apex and wings cells (between 2 to 4) clues combination.

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4.97...3.1....24....7.......91..5...6...3...5...6..84.......7....32....6.5...93.8
0) Apply Hidden Single Cell 62 Clue 4 from Clues 1249
10) Found Box-Line Reduction Intersection Removal Cells 30 31 32 drop Clue 4 from Cells 39 40 41 48 49 50
50) Found Pointing and Claiming Intersection Removal Cells 61 70 79 drop Clue 2 from Cells 7 16 25 34 43 52
 +---------------+---------------------+-------------------+
 | 4    268  9   | 7      1568   168   | 1256  3     12    |
 | 1    368  568 | 3589   5689   2     | 4     56789 79    |
 | 2358 2368 7   | 134589 145689 13468 | 12569 15689 129   |
 +---------------+---------------------+-------------------+
 | 2378 9    1   |a48     2478   5     | 26    67    237   |
 | 6    2478 248 |-189    3     w178   | 129   179   5     |
 | 2357 237  25  |-6      1279  w17    | 8     4     12379 |
 +---------------+---------------------+-------------------+
 | 289  1268 268 | 1358   1568  -1368  | 7     1259  4     |
 | 789  1478 3   | 2      14578 -1478  | 159   159   6     |
 | 27   5    246 |w14     1467  -9     | 3     12    8     |
 +---------------+---------------------+-------------------+
20) Found WXYZ-Wings Type 2a Cells 30 41 75 50 Clues 1478 drop Clue 1 from Cells 39 48 59 68 77
 +---------------+---------------------+-------------------+
 | 4    268  9   | 7      1568   168   | 1256  3     12    |
 | 1    368  568 | 3589   5689   2     | 4     56789 79    |
 | 2358 2368 7   | 134589 145689 13468 | 12569 15689 129   |
 +---------------+---------------------+-------------------+
 | 2378 9    1   | 48     2478   5     | 26    67    237   |
 | 6    2478 248 | 89     3      178   | 129   179   5     |
 | 2357 237  25  | 6      1279   17    | 8     4     12379 |
 +---------------+---------------------+-------------------+
 | 289  1268 268 | 1358   1568   368   | 7     1259  4     |
 | 789  1478 3   | 2      14578  478   | 159   159   6     |
 | 27   5    246 | 14     1467   9     | 3     12    8     |
 +---------------+---------------------+-------------------+

Sorry for bad impression due step description not meet the standard.

Actually, I started coded my solver just like zhouyundong_2012 ZSolver, gsf Sudoku, Brian Turner BB_Sudoku, JasonLion JSolve, Mladen Dobrichev fsss2, etc., that gives neither intermediate steps nor solution.

Where as, I inserted steps description and pencil mark printing for debugging the module in which I was working, and removed once code finalized. Later, I decided to include all debugging steps with pencil mark grid printing as debugging purpose only for sharing. The debugging option will be excluded or included on compile time.

My debug printing is based on strategy patterns. that's why it include all pattern based elimination cells instead of just those cells from where actually eliminations occurred. However, there is no programming issue to eliminate a clue from a cell that does not contain that clue, and later restore cell without change on backtracking rather than to check each eliminating cell for elimination clue presence, report, eliminate and restore..........

R. Jamil