Next move, please

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Next move, please

Postby QBasicMac » Tue Jan 31, 2006 4:33 am

Code: Select all
+----------+------------+------------+
| 7  2  6  | 3   58  4  | 58   9  1  |
| 3  8  5  | 16  9   12 | 7    4  26 |
| 9  4  1  | 78  67  25 | 568  3  28 |
+----------+------------+------------+
| 8  1  9  | 4   3   7  | 2    6  5  |
| 5  7  4  | 9   2   6  | 38   1  38 |
| 6  3  2  | 5   1   8  | 4    7  9  |
+----------+------------+------------+
| 4  6  37 | 18  58  15 | 9    2  37 |
| 2  9  8  | 67  4   3  | 1    5  67 |
| 1  5  37 | 2   67  9  | 36   8  4  |
+----------+------------+------------+


Thanks, Mac
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Postby eclark » Tue Jan 31, 2006 4:51 am

Here is what I found.

Code: Select all


+----------+------------+------------+
| 7  2  6  | 3  +58  4  | 58   9  1  |
| 3  8  5  | 16  9   12 | 7    4  26 |
| 9  4  1  | 78  67 *25 | 568  3 +28 |
+----------+------------+------------+
| 8  1  9  | 4   3   7  | 2    6  5  |
| 5  7  4  | 9   2   6  | 38   1  38 |
| 6  3  2  | 5   1   8  | 4    7  9  |
+----------+------------+------------+
| 4  6  37 | 18  58  15 | 9    2  37 |
| 2  9  8  | 67  4   3  | 1    5  67 |
| 1  5  37 | 2   67  9  | 36   8  4  |
+----------+------------+------------+


[XYwing] There is an XY-wing unsing a house row with stem 3x6 and ends 1x5 and 3x9. 
        [Removal] 1x7 Origional Posibility (58) After removals (5)
        [Removal] 3x4 Origional Posibility (78) After removals (7)
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Re: Next move, please

Postby tso » Tue Jan 31, 2006 5:32 am

QBasicMac wrote:
Code: Select all
+----------+------------+------------+
| 7  2  6  | 3   58  4  | 58   9  1  |
| 3  8  5  | 16  9   12 | 7    4  26 |
| 9  4  1  | 78  67  25 | 568  3  28 |
+----------+------------+------------+
| 8  1  9  | 4   3   7  | 2    6  5  |
| 5  7  4  | 9   2   6  | 38   1  38 |
| 6  3  2  | 5   1   8  | 4    7  9  |
+----------+------------+------------+
| 4  6  37 | 18  58  15 | 9    2  37 |
| 2  9  8  | 67  4   3  | 1    5  67 |
| 1  5  37 | 2   67  9  | 36   8  4  |
+----------+------------+------------+



BUG says that r3c7=8, solving the puzzle.

This puzzle was disected beyond all reason here.
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Postby tarek » Wed Feb 01, 2006 12:53 am

This solves it,
Code: Select all
*-----------------------------------------------*
| 7    2    6   | 3    58   4   | 58   9    1   |
| 3    8    5   | 16   9    12  | 7    4    26  |
| 9    4    1   | 78   67   25  | 568  3    28  |
|---------------+---------------+---------------|
| 8    1    9   | 4    3    7   | 2    6    5   |
| 5    7    4   | 9    2    6   | 38   1    38  |
| 6    3    2   | 5    1    8   | 4    7    9   |
|---------------+---------------+---------------|
| 4    6    37  | 18   58   15  | 9    2    37  |
| 2    9    8   | 67   4    3   | 1    5    67  |
| 1    5    37  | 2    67   9   | 36   8    4   |
*-----------------------------------------------*
Eliminating 8 From r3c4 (2 & 5 in r3c6 form an XY wing with 8 in r3c9 & r1c5)
Eliminating 8 From r1c7 (2 & 5 in r3c6 form an XY wing with 8 in r3c9 & r1c5)
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Postby QBasicMac » Wed Feb 01, 2006 6:46 am

tarek wrote:This solves it


True, but it is the identical solution already posted by EClark. I guess you figured I couldn't understand his/her notation, but actually I found it refreshing and concise.

I didn't reply because I was trying to understand why and how XY-Wings work (for the zillionth time - I keep losing it).

Got it again, so thanks EClark and tarek.

Mac
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Postby angusj » Wed Feb 01, 2006 6:56 am

QBasicMac wrote:I didn't reply because I was trying to understand why and how XY-Wings work (for the zillionth time - I keep losing it).

Just in case ... http://forum.enjoysudoku.com/viewtopic.php?p=17589#p17589
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Postby tarek » Wed Feb 01, 2006 1:47 pm

QBasicMac wrote:I guess you figured I couldn't understand his/her notation


No that was not the case. It was just a case of myself not noticing what was posted earlier [ooops:D ]
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Postby QBasicMac » Wed Feb 01, 2006 1:50 pm

Thanks. Yeah, I remember that thread. For some reason, I didn't get it fully there. But it finally soaked in with this example. (At least for today)

Mac
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