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keith
Joined: 19 Sep 2005 Posts: 3355 Location: near Detroit, Michigan, USA
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Posted: Wed Aug 03, 2011 1:41 pm Post subject: Free Press July 27, 2011 |
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I'm back. This one seems to be on the tough side: Code: | Puzzle: FP072911
+-------+-------+-------+
| . . . | . . 8 | . 9 . |
| . . 2 | 6 7 . | . . . |
| . . 8 | . . . | 7 . . |
+-------+-------+-------+
| . . 9 | . . 5 | 1 . 8 |
| 8 . 4 | 3 . 9 | 2 . 7 |
| 3 . 7 | 8 . . | 4 . . |
+-------+-------+-------+
| . . 1 | . . . | 5 . . |
| . . . | . 6 7 | 9 . . |
| . 4 . | 2 . . | . . . |
+-------+-------+-------+
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Play this puzzle online at the Daily Sudoku site
Keith |
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Marty R.
Joined: 12 Feb 2006 Posts: 5770 Location: Rochester, NY, USA
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Posted: Wed Aug 03, 2011 5:14 pm Post subject: |
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I couldn't come up with a totally satisfying solution. After a W-Wing, X-Wing and XY-Wing, I couldn't find any conventional moves. So I looked at the potential 14 DP in boxes 13. The 5s in r23c1 were invalid as DP killers; r23c1<>5. |
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daj95376
Joined: 23 Aug 2008 Posts: 3854
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Posted: Wed Aug 03, 2011 8:24 pm Post subject: |
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Welcome back Keith !!!
An interesting puzzle with a difficult last step. |
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Marty R.
Joined: 12 Feb 2006 Posts: 5770 Location: Rochester, NY, USA
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Posted: Wed Aug 03, 2011 9:50 pm Post subject: |
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P.S. Due to my laziness and dislike of the process, I did not check rows and columns for X-Wings, Skyscrapers and other potential moves that those checks could reveal. The X-Wing that I did use was very obvious. |
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Clement
Joined: 24 Apr 2006 Posts: 1111 Location: Dar es Salaam Tanzania
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Posted: Thu Aug 04, 2011 12:49 pm Post subject: Free Press July 27, 2011 |
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Marty,
After the Basics:-
Code: | +----------------+---------------+----------------+
| 14 7 356 | 14 35 8 | 36 9 2 |
| 1459 39 2 | 6 7 134 | 38 148 1345 |
| 1456 36 8 | 1459 359 2 | 7 14 13456 |
+----------------+---------------+----------------+
| 26 26 9 | 7 4 5 | 1 3 8 |
| 8 5 4 | 3 1 9 | 2 6 7 |
| 3 1 7 | 8 2 6 | 4 5 9 |
+----------------+---------------+----------------+
| 2679 23689 1 | 49 389 34 | 5 2478 346 |
| 25 238 35 | 145 6 7 | 9 1248 134 |
| 5679 4 356 | 2 3589 13 | 368 178 136 |
+----------------+---------------+----------------+ |
I do not see any W-Wing or X-Wing |
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Marty R.
Joined: 12 Feb 2006 Posts: 5770 Location: Rochester, NY, USA
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Posted: Thu Aug 04, 2011 1:57 pm Post subject: Re: Free Press July 27, 2011 |
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Clement wrote: | Marty,
After the Basics:-
Code: | +----------------+---------------+----------------+
| 14 7 356 | 14 35 8 | 36 9 2 |
| 1459 39 2 | 6 7 134 | 38 148 1345 |
| 1456 36 8 | 1459 359 2 | 7 14 13456 |
+----------------+---------------+----------------+
| 26 26 9 | 7 4 5 | 1 3 8 |
| 8 5 4 | 3 1 9 | 2 6 7 |
| 3 1 7 | 8 2 6 | 4 5 9 |
+----------------+---------------+----------------+
| 2679 23689 1 | 49 389 34 | 5 2478 346 |
| 25 238 35 | 145 6 7 | 9 1248 134 |
| 5679 4 356 | 2 3589 13 | 368 178 136 |
+----------------+---------------+----------------+ |
I do not see any W-Wing or X-Wing |
Clement,
The W-Wing is on the 35s in boxes 27, connected by the 5s in r9.
The X-Wing is on 6s in c37. |
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Clement
Joined: 24 Apr 2006 Posts: 1111 Location: Dar es Salaam Tanzania
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Posted: Thu Aug 04, 2011 11:14 pm Post subject: Free Press Jul 27, 2011 |
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Marty,
Ooo Yes, I can see them. However, the 5s connecting the 35s in my Grid are in col 4. Thank you. |
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daj95376
Joined: 23 Aug 2008 Posts: 3854
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Posted: Thu Aug 04, 2011 11:35 pm Post subject: |
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I didn't check to see how many of my solver's intermediate steps were needed to reach the "right" UR state.
Code: | after basics
+-----------------------------------------------------------------------+
| 14 7 356 | 14 35 8 | 36 9 2 |
| 1459 39 2 | 6 7 134 | 38 148 1345 |
| 1456 36 8 | 1459 359 2 | 7 14 13456 |
|-----------------------+-----------------------+-----------------------|
| 26 26 9 | 7 4 5 | 1 3 8 |
| 8 5 4 | 3 1 9 | 2 6 7 |
| 3 1 7 | 8 2 6 | 4 5 9 |
|-----------------------+-----------------------+-----------------------|
| 2679 23689 1 | 49 389 34 | 5 2478 346 |
| 25 238 35 | 145 6 7 | 9 1248 134 |
| 5679 4 356 | 2 3589 13 | 368 178 136 |
+-----------------------------------------------------------------------+
# 76 eliminations remain
c37 X-Wing <> 6 r9c19
<25+6> XY-Wing r8c1/r4c1+r9c3 <> 6 r7c1
r1c4 2-String Kite <> 5 r8c3
<56+3> XY-Wing r1c3/r1c5+r3c2 <> 3 r3c5
r19 X-Wing <> 5 r3c5
<28> UR in r78c28
+--------------------------------------------------------------+
| 14 7 56 | 14 35 8 | 36 9 2 |
| 145 9 2 | 6 7 134 | 38 148@ 145 |
| 1456 3 8 | 145 9 2 | 7 14 1456 |
|--------------------+--------------------+--------------------|
| 26 @26 9 | 7 4 5 | 1 3 8 |
| 8 5 4 | 3 1 9 | 2 6 7 |
| 3 1 7 | 8 2 6 | 4 5 9 |
|--------------------+--------------------+--------------------|
| 7 *28+6 1 | 9 38 34 | 5 *28+4 346 |
| 25 *28 3 | 145 6 7 | 9 *28+14 14 |
| 9 4 56 | 2 58 13 | 68 7 13 |
+--------------------------------------------------------------+
# 46 eliminations remain
(2 )r7c2 = (2-8)r7c8
/ \
(8)r2c8 =UR= (2)r4c2 - = (8)r2c8
\ /
(2=8)r8c3 - ( 8)r8c8
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An alternate viewpoint:
Code: | strong link on <2> in [r7] and [c8] strong link on <8> in [r8] and [c2]
+-----------------------------------+ +-----------------------------------+
| . . . | . . . | . / 2 | | . / . | . . 8 | . . . |
| . . 2 | . . . | . / . | | . / . | . . . | 8 8 . |
| . . . | . . 2 | . / . | | . / 8 | . . . | . . . |
|-----------+-----------+-----------| |-----------+-----------+-----------|
| 2 2 . | . . . | . / . | | . / . | . . . | . . 8 |
| . . . | . . . | 2 / . | | 8 / . | . . . | . . . |
| . . . | . 2 . | . / . | | . / . | 8 . . | . . . |
|-----------+-----------+-----------| |-----------+-----------+-----------|
| / 2 / | / / / | / 2 / | | . 8 . | . 8 . | . 8 . |
| 2 2 . | . . . | . 2 . | | / 8 / | / / / | / 8 / |
| . . . | 2 . . | . / . | | . / . | . 8 . | 8 . . |
+-----------------------------------+ +-----------------------------------+
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If r7c2=8 or r7c8=8, then the strong links (and bivalue in r8c2) will force a <28> DP.
Thus, we can perform r7c2<>8 and r7c8<>8. |
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Marty R.
Joined: 12 Feb 2006 Posts: 5770 Location: Rochester, NY, USA
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Posted: Fri Aug 05, 2011 12:33 am Post subject: |
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Quote: | Ooo Yes, I can see them. However, the 5s connecting the 35s in my Grid are in col 4. Thank you. |
They were probably in my grid too. Either way gets the job done. |
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Marty R.
Joined: 12 Feb 2006 Posts: 5770 Location: Rochester, NY, USA
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Posted: Fri Aug 05, 2011 1:16 am Post subject: |
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This is where I find myself after a W-Wing, X-Wing, XY-Wing, Fin Transport and short XY-Chain. |
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