Help please

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Help please

Postby jakesprake » Mon Nov 13, 2017 3:49 pm

Hi
Does anyone understand this?
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jakesprake
 
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Re: Help please

Postby pjb » Tue Nov 14, 2017 9:06 pm

Code: Select all
 6       4       1258   | 258    9      158    | 12     7      3     
 7       3       128    | 268    4      168    | 126    9      5     
 125     25      9      | 2567   13     37     | 4      1268   18     
------------------------+----------------------+---------------------
 145     578     156    | 3      58     2      | 15679  1568   1489   
 9       58      135    | 46     7      46     | 135    158    2     
 245     2578    2356   | 1      58     9      | 3567   568    48     
------------------------+----------------------+---------------------
 25      6       4      | 579    13     37     | 8      125    19     
 3       1       7      | 589    2      58     | 59     4      6     
 8       9       25     | 45     6      145    | 125    3      7     


Above is state after naked singles, hidden singles, box-line moves and naked/hiden sets, ie the basic set of moves. After that there are choices: a number of short chains or a single chain of length 6:
(1)r3c1 = (1-4)r4c1 = r4c9 - (4=8)r6c9 - (8=1)r3c9 - r3c1 => -5 r3c58, r4c1
However, for manual solving I rather prefer the Swordfish of 1s at r1c367, r2c367, r9c67 eliminating 1 from r45c37. The puzzle solves with singles after that.
Phil
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Re: Help please

Postby Leren » Wed Nov 15, 2017 1:12 am

The puzzle solved cell status in line format : 64..9..7373..4..95..9...4.....3.2...9...7...2...1.9....64...8..317.2..4689..6..37

The following diagram shows the Swordfish that solves the puzzle :

Code: Select all
*--------------------------------------------------*
| 6   4    *1258 | 258  9  *158 |*12     7    3    |
| 7   3    *128  | 268  4  *168 |*126    9    5    |
| 125 25    9    | 2567 13  37  | 4      1268 18   |
|----------------+--------------+------------------|
| 145 578   56-1 | 3    58  2   | 5679-1 1568 1489 |
| 9   58    35-1 | 46   7   46  | 35-1   158  2    |
| 245 2578  2356 | 1    58  9   | 3567   568  48   |
|----------------+--------------+------------------|
| 25  6     4    | 579  13  37  | 8      125  19   |
| 3   1     7    | 589  2   58  | 59     4    6    |
| 8   9     25   | 45   6  *145 |*125    3    7    |
*--------------------------------------------------*

Leren

<edit>

Now that I've read your original question I can go back a bit. I can't understand what the solver is saying but there is an easy way to eliminate the 1 from r7c6, and a lot more besides.

Code: Select all
*---------------------------------------------------*
| 6   4    1258 | 258  9   158    | 12    7    3    |
| 7   3    128  | 268  4   168    | 126   9    5    |
| 125 25   9    | 2567 13 *37-156 | 4     1268 18   |
|---------------+-----------------+-----------------|
| 145 578  156  | 3    58  2      | 15679 1568 1489 |
| 9   58   135  | 46   7   46     | 135   158  2    |
| 245 2578 2356 | 1    58  9      | 3567  568  48   |
|---------------+-----------------+-----------------|
| 25  6    4    | 579  13 *37-15  | 8     125  19   |
| 3   1    7    | 589  2   58     | 59    4    6    |
| 8   9    25   | 45   6   145    | 125   3    7    |
*---------------------------------------------------*

There is a hidden pair (37) in r47c6, so you can eliminate all other digits from those two cells. That's a pretty basic move, so I'm not quite sure why the solver did not suggest it. This move exposes the Swordfish.

Leren
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Re: Help please

Postby jakesprake » Wed Nov 15, 2017 11:35 am

Thanks Laren
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Re: Help please

Postby eleven » Wed Nov 15, 2017 9:33 pm

I don't quite understand the solver's logic, but coloring in 1 gives it's result, and is a 1-step solution.
Code: Select all
+-------------------------+-------------------------+-------------------------+
| 6       4       1258    | 258     9       158     | 12      7       3       |
| 7       3       128     | 268     4       168     | 126     9       5       |
| 25-1    258     9       | 25678  A1358    135678  | 4      B1268   B18      |
+-------------------------+-------------------------+-------------------------+
| 145     578     1568    | 3       58      2       | 15679   1568    1489    |
| 9       58      13568   | 4568    7       4568    | 1356    1568    2       |
| 245     2578    23568   | 1       58      9       | 3567    568     48      |
+-------------------------+-------------------------+-------------------------+
| 25      6       4       | 579     135     1357    | 8       125     19      |
| 3       1       7       | 589     2       58      | 59      4       6       |
| 8       9       25      | 45      6      A145     |B125     3       7       |
+-------------------------+-------------------------+-------------------------+

1 is in r9c6 or r9c7.
If in r9c6 then also in r3c5 (box2).
If in r9c7, then also in r3c89 (box3).
So it must be in one of r3c589 and cannot be in r3c1 (or r3c6).
Thus 1 must be in r4c1 and you have singles to the end.
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