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Set D Puzzle 3

 
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daj95376



Joined: 23 Aug 2008
Posts: 3855

PostPosted: Tue Dec 02, 2008 4:40 am    Post subject: Set D Puzzle 3 Reply with quote

Swordfish Alert.

Code:
 +-----------------------+
 | 1 8 . | . . . | 5 7 . |
 | 3 5 . | . 8 . | 2 . 6 |
 | . . . | . . . | . . 8 |
 |-------+-------+-------|
 | . . . | . . . | . . . |
 | . 3 . | . . 5 | 8 2 . |
 | . . . | . 2 3 | 1 . 5 |
 |-------+-------+-------|
 | 9 2 . | . 5 8 | 4 . 1 |
 | 5 . . | . 9 . | . . . |
 | . 4 8 | . . 2 | 7 . . |
 +-----------------------+

Play this puzzle online at the Daily Sudoku site
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storm_norm



Joined: 18 Oct 2007
Posts: 1741

PostPosted: Tue Dec 02, 2008 7:03 am    Post subject: Reply with quote

Code:
.---------------------.---------------------.---------------------.
| 1      8      69    | 2      34     69    | 5      7      34    |
| 3      5      479   | 1479   8      1479  | 2      149    6     |
| 47     679    2     | 5      347    14679 | 39     1349   8     |
:---------------------+---------------------+---------------------:
| 2      1679   5     | 8      47     1479  | 369    3469   347   |
| 47     3      19    | 19     6      5     | 8      2      47    |
| 8      679    4679  | 479    2      3     | 1      469    5     |
:---------------------+---------------------+---------------------:
| 9      2      37    | 67     5      8     | 4      36     1     |
| 5      17     137   | 467    9      47    | 36     8      2     |
| 6      4      8     | 3      1      2     | 7      5      9     |
'---------------------'---------------------'---------------------'

that swordfish alert is also a DP alert for {4,7}, but the common candiate 3 in r3c5 and r4c9 don't really make any interesting inferences? do they?
Quote:
w-wing on {4,7} removes 7 from r4c9

leaves...
Code:
.------------------.------------------.------------------.
| 1     8    #69   | 2     34   #69   | 5     7     34   |
| 3     5     4    |17-9   8    17-9  | 2    #19    6    |
| 7     69    2    | 5     34   #169  | 39   #1349  8    |
:------------------+------------------+------------------:
| 2     169   5    | 8     7    #149  | 369   3469  34   |
| 4     3    #19   |#19    6     5    | 8     2     7    |
| 8     679   679  | 49    2     3    | 1     469   5    |
:------------------+------------------+------------------:
| 9     2     37   | 67    5     8    | 4     36    1    |
| 5     17    137  | 467   9     47   | 36    8     2    |
| 6     4     8    | 3     1     2    | 7     5     9    |
'------------------'------------------'------------------'

Quote:
the extended w-wing through kite strong links on 1
(9=1)r2c8 - (1)r3c8 = (1)r3c6 - (1)r4c6 = (1)r5c4 - (1=9) - (9)r1c3 = (9)r1c6; r2c46 <> 6
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daj95376



Joined: 23 Aug 2008
Posts: 3855

PostPosted: Tue Dec 02, 2008 3:24 pm    Post subject: Reply with quote

storm_norm wrote:
that swordfish alert is also a DP alert for {4,7}, but the common candiate 3 in r3c5 and r4c9 don't really make any interesting inferences? do they?

Nice catch on the DP. My limited experience with DPs couldn't make anything of the conjugate 3s. Maybe someone else will see something.

BTW: I corrected a typo where you wrote r5c9 instead of r4c9. I hope this is acceptable. I'm not sure what's acceptable with my expanded capabilities as a forum moderator. I'm open to suggestions on what to do in the future!
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storm_norm



Joined: 18 Oct 2007
Posts: 1741

PostPosted: Tue Dec 02, 2008 8:31 pm    Post subject: Reply with quote

Quote:
I corrected a typo where you wrote r5c9 instead of r4c9

good catch on your part as well.
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Marty R.



Joined: 12 Feb 2006
Posts: 5164
Location: Rochester, NY, USA

PostPosted: Tue Dec 02, 2008 10:27 pm    Post subject: Reply with quote

Quote:
BTW: I corrected a typo where you wrote r5c9 instead of r4c9. I hope this is acceptable. I'm not sure what's acceptable with my expanded capabilities as a forum moderator. I'm open to suggestions on what to do in the future!

Use your judgment, we have few rules that have been handed down. However, if you edit someone's post, type an explanation at the bottom, such as, "Edited by daj to correct cell number from r5c9 to r4c9."
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daj95376



Joined: 23 Aug 2008
Posts: 3855

PostPosted: Tue Dec 02, 2008 10:34 pm    Post subject: Reply with quote

Marty R. wrote:
Quote:
BTW: I corrected a typo where you wrote r5c9 instead of r4c9. I hope this is acceptable. I'm not sure what's acceptable with my expanded capabilities as a forum moderator. I'm open to suggestions on what to do in the future!

Use your judgment, we have few rules that have been handed down. However, if you edit someone's post, type an explanation at the bottom, such as, "Edited by daj to correct cell number from r5c9 to r4c9."

I like it ... Exclamation
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arkietech



Joined: 31 Jul 2008
Posts: 1727
Location: Northwest Arkansas USA

PostPosted: Wed Dec 03, 2008 12:40 am    Post subject: Reply with quote

storm_norm wrote:
Code:
.---------------------.---------------------.---------------------.
| 1      8      69    | 2      34     69    | 5      7      34    |
| 3      5      479   | 1479   8      1479  | 2      149    6     |
| 47     679    2     | 5      347    14679 | 39     1349   8     |
:---------------------+---------------------+---------------------:
| 2      1679   5     | 8      47     1479  | 369    3469   34-7  |
|*47     3      19    | 19     6      5     | 8      2     *47    |
| 8      679    4679  | 479    2      3     | 1      469    5     |
:---------------------+---------------------+---------------------:
| 9      2      37    | 67     5      8     | 4      36     1     |
| 5      17     137   | 467    9      47    | 36     8      2     |
| 6      4      8     | 3      1      2     | 7      5      9     |
'---------------------'---------------------'---------------------'
w-wing on {4,7} removes 7 from r4c9

Still struggling with w-wings. Looks like if r4c9<>7 then r5c9=7
Is this right? Can someone show me the logic?
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Marty R.



Joined: 12 Feb 2006
Posts: 5164
Location: Rochester, NY, USA

PostPosted: Wed Dec 03, 2008 12:50 am    Post subject: Reply with quote

arkietech wrote:
storm_norm wrote:
Code:
.---------------------.---------------------.---------------------.
| 1      8      69    | 2      34     69    | 5      7      34    |
| 3      5      479   | 1479   8      1479  | 2      149    6     |
| 47     679    2     | 5      347    14679 | 39     1349   8     |
:---------------------+---------------------+---------------------:
| 2      1679   5     | 8      47     1479  | 369    3469   34-7  |
|*47     3      19    | 19     6      5     | 8      2     *47    |
| 8      679    4679  | 479    2      3     | 1      469    5     |
:---------------------+---------------------+---------------------:
| 9      2      37    | 67     5      8     | 4      36     1     |
| 5      17     137   | 467    9      47    | 36     8      2     |
| 6      4      8     | 3      1      2     | 7      5      9     |
'---------------------'---------------------'---------------------'
w-wing on {4,7} removes 7 from r4c9

Still struggling with w-wings. Looks like if r4c9<>7 then r5c9=7
Is this right? Can someone show me the logic?

The 47 cells in boxes 56 are connected by the strong link on 4 in row 1. Because of those 4s in row 1, one or the other of the 47 cells must be = 7, thus the pincer situation.
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arkietech



Joined: 31 Jul 2008
Posts: 1727
Location: Northwest Arkansas USA

PostPosted: Wed Dec 03, 2008 3:03 am    Post subject: Reply with quote

Marty R. wrote:
arkietech wrote:
storm_norm wrote:
Code:
.---------------------.---------------------.---------------------.
| 1      8      69    | 2      34     69    | 5      7      34    |
| 3      5      479   | 1479   8      1479  | 2      149    6     |
| 47     679    2     | 5      347    14679 | 39     1349   8     |
:---------------------+---------------------+---------------------:
| 2      1679   5     | 8      47     1479  | 369    3469   34-7  |
|*47     3      19    | 19     6      5     | 8      2     *47    |
| 8      679    4679  | 479    2      3     | 1      469    5     |
:---------------------+---------------------+---------------------:
| 9      2      37    | 67     5      8     | 4      36     1     |
| 5      17     137   | 467    9      47    | 36     8      2     |
| 6      4      8     | 3      1      2     | 7      5      9     |
'---------------------'---------------------'---------------------'
w-wing on {4,7} removes 7 from r4c9

Still struggling with w-wings. Looks like if r4c9<>7 then r5c9=7
Is this right? Can someone show me the logic?

The 47 cells in boxes 56 are connected by the strong link on 4 in row 1. Because of those 4s in row 1, one or the other of the 47 cells must be = 7, thus the pincer situation.

Thanks, I was looking at the wrong 47. I have some kind of mental barrier to all this.
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