| View previous topic :: View next topic | 
	
	
		| Author | Message | 
	
		| keith 
 
 
 Joined: 19 Sep 2005
 Posts: 3355
 Location: near Detroit, Michigan, USA
 
 | 
			
				|  Posted: Mon Jul 22, 2013 3:26 pm    Post subject: Free Press July 19, 2013 |   |  
				| 
 |  
				| Not yet started ... 
 
  	  | Code: |  	  | Puzzle: FP071913 +-------+-------+-------+
 | 7 . . | . . . | . 5 4 |
 | . . . | 8 . 5 | . . 6 |
 | . . . | . 2 . | 7 . . |
 +-------+-------+-------+
 | 1 . 3 | . 8 . | 9 . . |
 | . . . | 9 . 7 | . . . |
 | . . 4 | . 6 . | 2 . 3 |
 +-------+-------+-------+
 | . . 7 | . . . | . . . |
 | 8 . . | 1 5 3 | . . . |
 | 4 3 . | . . . | . . 8 |
 +-------+-------+-------+
 
 | 
 Play this puzzle online at the Daily Sudoku site
 
 Keith
 |  | 
	
		| Back to top |  | 
	
		|  | 
	
		| keith 
 
 
 Joined: 19 Sep 2005
 Posts: 3355
 Location: near Detroit, Michigan, USA
 
 | 
			
				|  Posted: Mon Jul 22, 2013 9:41 pm    Post subject: |   |  
				| 
 |  
				| Solved by multiple attacks on 6. 
 Keith
 |  | 
	
		| Back to top |  | 
	
		|  | 
	
		| Marty R. 
 
 
 Joined: 12 Feb 2006
 Posts: 5770
 Location: Rochester, NY, USA
 
 | 
			
				|  Posted: Tue Jul 23, 2013 1:08 am    Post subject: |   |  
				| 
 |  
				| This is the same puzzle that Dan posted on the other site as L.A. Times Diabolical of 7-19 and I've been struggling with that. |  | 
	
		| Back to top |  | 
	
		|  | 
	
		| Marty R. 
 
 
 Joined: 12 Feb 2006
 Posts: 5770
 Location: Rochester, NY, USA
 
 | 
			
				|  Posted: Tue Jul 23, 2013 1:24 am    Post subject: |   |  
				| 
 |  
				| I struggled, using a W-Wing on 26, an XY-Wing on 25-6 and an XY-Loop that started and ended in c1. |  | 
	
		| Back to top |  | 
	
		|  | 
	
		| keith 
 
 
 Joined: 19 Sep 2005
 Posts: 3355
 Location: near Detroit, Michigan, USA
 
 | 
			
				|  Posted: Tue Jul 23, 2013 11:12 am    Post subject: |   |  
				| 
 |  
				| After basics: 
  	  | Code: |  	  | +-------------------+-------------------+-------------------+ | 7     268   268   | 36    1     9     | 38    5     4     |
 | 3     4     9     | 8     7     5     | 1     2     6     |
 | 56    1568  1568  | 346   2     46    | 7     38    9     |
 +-------------------+-------------------+-------------------+
 | 1     567   3     | 24    8     24    | 9     67    57    |
 | 256   2568  2568  | 9     3     7     | 4568  1468  15    |
 | 9     78    4     | 5     6     1     | 2     78    3     |
 +-------------------+-------------------+-------------------+
 |25-6  125-69 7     |#26    4     8     | 356   1369  125   |
 | 8     269  #26    | 1     5     3     | 46    4679  27    |
 | 4     3    *1256  | 7     9    *26    | 56    16    8     |
 +-------------------+-------------------+-------------------+
 | 
 W-wing.
 
 After that, two XY-wings 25-6 and 25-6 leave us here:
 
  	  | Code: |  	  | +----------------+----------------+----------------+ | 7   #268  28   |#36   1    9    | 38   5    4    |
 | 3    4    9    | 8    7    5    | 1    2    6    |
 | 56   1568 158  | 34   2    46   | 7    38   9    |
 +----------------+----------------+----------------+
 | 1   *567  3    | 24   8    24   | 9   *67   57   |
 | 256  2568 2568 | 9    3    7    | 4568 1468 15   |
 | 9    78   4    | 5    6    1    | 2    78   3    |
 +----------------+----------------+----------------+
 | 25   1259 7    |#26   4    8    | 356  1369 125  |
 | 8    269  26   | 1    5    3    | 46   4679 27   |
 | 4    3    1256 | 7    9   #26   | 56  1-6   8    |
 +----------------+----------------+----------------+
 | 
 Multicoloring (Extended skyscraper) takes out 6 in R9C8.
 
 Keith
 |  | 
	
		| Back to top |  | 
	
		|  | 
	
		| tlanglet 
 
 
 Joined: 17 Oct 2007
 Posts: 2468
 Location: Northern California Foothills
 
 | 
			
				|  Posted: Tue Jul 23, 2013 12:35 pm    Post subject: |   |  
				| 
 |  
				| I believe that we call this a xy-wing(67-1) with pseudocell pincer (17)r45c9...... 
 
  	  | Code: |  	  | *--------------------------------------------------------------------*
 | 7      268    268    | 36     1      9      | 38     5      4      |
 | 3      4      9      | 8      7      5      | 1      2      6      |
 | 56     1568   1568   | 346    2      46     | 7      38     9      |
 |----------------------+----------------------+----------------------|
 | 1      567    3      | 24     8      24     | 9     b67    c57     |
 | 256    2568   2568   | 9      3      7      | 4568  -1468  d15     |
 | 9      78     4      | 5      6      1      | 2      78     3      |
 |----------------------+----------------------+----------------------|
 | 256    12569  7      | 26     4      8      | 356    1369  -125    |
 | 8      269    26     | 1      5      3      | 46     4679   27     |
 | 4      3      1256   | 7      9      26     | 56    a16     8      |
 *--------------------------------------------------------------------*
 
 | 
 xy-wing(76-1):  (1=6)r9c8-(6=7)r4c8-(7=5)r4c9-(5=1)r5c9 => r5c8,r7c9<>1
 
 Ted
 |  | 
	
		| Back to top |  | 
	
		|  | 
	
		| keith 
 
 
 Joined: 19 Sep 2005
 Posts: 3355
 Location: near Detroit, Michigan, USA
 
 | 
			
				|  Posted: Tue Jul 23, 2013 3:21 pm    Post subject: |   |  
				| 
 |  
				| Ted, 
 Very nice!
 
 I must say though that the way I solve puzzles would tend to find the solution I posted, not a short chain like yours.
 
 Keith
 |  | 
	
		| Back to top |  | 
	
		|  | 
	
		| Marty R. 
 
 
 Joined: 12 Feb 2006
 Posts: 5770
 Location: Rochester, NY, USA
 
 | 
			
				|  Posted: Tue Jul 23, 2013 6:10 pm    Post subject: |   |  
				| 
 |  
				|  	  | keith wrote: |  	  | Ted, 
 Very nice!
 
 I must say though that the way I solve puzzles would tend to find the solution I posted, not a short chain like yours.
 
 Keith
 | 
 
 I might've found the chain if I reached the point where looking for chains was my only option, but I'd never have recognized it as an XY-Wing with pseudo cell pincer.
 |  | 
	
		| Back to top |  | 
	
		|  | 
	
		| tlanglet 
 
 
 Joined: 17 Oct 2007
 Posts: 2468
 Location: Northern California Foothills
 
 | 
			
				|  Posted: Tue Jul 23, 2013 8:45 pm    Post subject: |   |  
				| 
 |  
				| I was checking for xy-wings when I noted the solution. It just jumped out at me since three of the four cells were literally adjacent in box 6. In any case, I normally/frequently look one step past a bivalue cell that is useful but does not complete the xy-wing, and if the additional step is successful, I will continue the process looking for a useful xy-chain. 
 Ted
 |  | 
	
		| Back to top |  | 
	
		|  | 
	
		|  |