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June 27, VH

 
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prakash



Joined: 02 Jan 2008
Posts: 67
Location: New Jersey, USA

PostPosted: Fri Jun 27, 2008 12:55 am    Post subject: June 27, VH Reply with quote

I am sure I missed something simple. I had to jump through hoops to get his done. 2 XYZ wings, 1 X Wing and 1 XY Wing. Anybody spot something simpler?

XYZ Wing 13-143-43 removes 3 from R3C7
X Wing on 3 removes 3 from R2C5
XYZ Wing 49-479-79 removes 9 from R3C7
XY Wing 17-27-12 removes 1 from R1C5
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wapati



Joined: 10 Jun 2008
Posts: 472
Location: Brampton, Ontario, Canada.

PostPosted: Fri Jun 27, 2008 4:40 am    Post subject: Re: June 27, VH Reply with quote

prakash wrote:
Anybody spot something simpler?


Shorter, yep. I find 2 string kites to be horribly hard to spot.

Code:
Simple stuff to here where a two string kite eliminates the 4 in r3c6.
.---------------------.---------------------.---------------------.
| 17     4      3     | 89     18     5     | 6      79     2     |
| 12     5      9     | 46     12346  7     | 134    8      13    |
| 6      27     8     | 49     1234  #12-4  | 1349  @479    5     |
:---------------------+---------------------+---------------------:
| 5      9      2     | 1      7     *48    |*34     6      38    |
| 478    678    46    | 2      5      3     | 149   @49     18    |
| 48     3      1     | 468    468    9     | 5      2      7     |
:---------------------+---------------------+---------------------:
| 248    268    46    | 5      12     126   | 7      3      9     |
| 9      1      7     | 3      48     468   | 2      5      46    |
| 3      26     5     | 7      9      246   | 8      1      46    |
'---------------------'---------------------'---------------------'



That sets up an xy wing that sets r1c5 to 8.  The rest is simple.

.---------------------.---------------------.---------------------.
|*17     4      3     | 89    #8-1    5     | 6      79     2     |
| 12     5      9     | 46     12346  7     | 134    8      13    |
| 6     *27     8     | 49     1234  *12    | 1349   479    5     |
:---------------------+---------------------+---------------------:
| 5      9      2     | 1      7      48    | 34     6      38    |
| 478    678    46    | 2      5      3     | 149    49     18    |
| 48     3      1     | 468    468    9     | 5      2      7     |
:---------------------+---------------------+---------------------:
| 248    268    46    | 5      12     126   | 7      3      9     |
| 9      1      7     | 3      48     468   | 2      5      46    |
| 3      26     5     | 7      9      246   | 8      1      46    |
'---------------------'---------------------'---------------------'
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Marty R.



Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA

PostPosted: Fri Jun 27, 2008 4:41 am    Post subject: Reply with quote

W-Wing, Type 4 UR, W-Wing. The UR probably wasn't needed.
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wapati



Joined: 10 Jun 2008
Posts: 472
Location: Brampton, Ontario, Canada.

PostPosted: Fri Jun 27, 2008 4:54 am    Post subject: Reply with quote

I so like it that different paths are often easy to find.

Sudoku would be stale if there was only one path and order. Sad

I confirm that the UR is not needed.
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storm_norm



Joined: 18 Oct 2007
Posts: 1741

PostPosted: Fri Jun 27, 2008 5:30 am    Post subject: Reply with quote

Code:
.---------------------.---------------------.---------------------.
|*17     4      3     | 89    *18     5     | 6      79     2     |
|#12     5      9     | 46    1-2346  7     | 134    8      13    |
| 6      27     8     | 49     1234   124   | 1349   479    5     |
:---------------------+---------------------+---------------------:
| 5      9      2     | 1      7      48    | 34     6      38    |
| 478    678    46    | 2      5      3     | 149    49     18    |
| 48     3      1     | 468    468    9     | 5      2      7     |
:---------------------+---------------------+---------------------:
| 248    268    46    | 5     #12     126   | 7      3      9     |
| 9      1      7     | 3      48     468   | 2      5      46    |
| 3      26     5     | 7      9      246   | 8      1      46    |
'---------------------'---------------------'---------------------'


w-wing {1,2} through the ones in the first row, removes 2 in r2c5

(2=1)r2c1-(1)r1c1=(1)r5c1-(1=2)r7c5; r2c5<>2
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nataraj



Joined: 03 Aug 2007
Posts: 1048
Location: near Vienna, Austria

PostPosted: Fri Jun 27, 2008 5:55 am    Post subject: Reply with quote

Something simple?

An xyz-wing very early on: 4,7,9 in row 3 + box 3, removes 9 from r3c7. From there, basic stuff for a while.

Near the end, either a UR (26 r79c26 with strong link 6 in r7) or an xy-wing pivot r3c2 (17-27-12)
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Johan



Joined: 25 Jun 2007
Posts: 206
Location: Bornem Belgium

PostPosted: Fri Jun 27, 2008 8:59 am    Post subject: Reply with quote

I used the strong link* on <2> in C1, which eliminates <1> in R1C5 collapsing the whole puzzle. Either R2C1=2 or R7C1=2.

R2C1=2 => R1C1=1(a)

R7C1=2 => R7C5=1(b)
Code:
+-------------------------+-------------------------+-------------------------+
| 17 a      4         3   | 89      -[1]8      5    | 6         79        2   |
|*12        5         9   | 46        12346    7    | 134       8         13  |
| 6         27        8   | 49        1234     124  | 1349      479       5   |
+-------------------------+-------------------------+-------------------------+
| 5         9         2   | 1         7        48   | 34        6         38  |
| 478       678       46  | 2         5        3    | 149       49        18  |
| 48        3         1   | 468       468      9    | 5         2         7   |
+-------------------------+-------------------------+-------------------------+
|*248       268       46  | 5         12 b     126  | 7         3         9   |
| 9         1         7   | 3         48       468  | 2         5         46  |
| 3         26        5   | 7         9        246  | 8         1         46  |
+-------------------------+-------------------------+-------------------------+
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cgordon



Joined: 04 May 2007
Posts: 769
Location: ontario, canada

PostPosted: Fri Jun 27, 2008 2:34 pm    Post subject: Reply with quote

Remarkably easy really. I simply used the following:

x-wing on <6>
xyz-wing on <134>
x-wing on <2>
ER on <4>
xy-wing on <127>

A three coffee job at most. Twisted Evil
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Earl



Joined: 30 May 2007
Posts: 677
Location: Victoria, KS

PostPosted: Fri Jun 27, 2008 4:31 pm    Post subject: VH Reply with quote

An xyz-wing (479), then an xy-wing (127) (all in boxes 1-2-3) did it for me.

Earl
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Clement



Joined: 24 Apr 2006
Posts: 1110
Location: Dar es Salaam Tanzania

PostPosted: Sat Jun 28, 2008 5:25 pm    Post subject: Daily Sudoku: Fri 27-Jun-2008 VH Reply with quote

I used the BUG Principle.Candidate 9 is the only one that appears three times in c8.Therefore, 9 must go in r3c8 which is the only three candidate cell in the column. That solves the puzzle.
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nataraj



Joined: 03 Aug 2007
Posts: 1048
Location: near Vienna, Austria

PostPosted: Sat Jun 28, 2008 6:02 pm    Post subject: Re: Daily Sudoku: Fri 27-Jun-2008 VH Reply with quote

Clement wrote:
I used the BUG Principle.Candidate 9 is the only one that appears three times in c8.Therefore, 9 must go in r3c8 which is the only three candidate cell in the column. That solves the puzzle.


"Careful with that axe, Eugene ..."

Clement, could you explain that a bit more? I do not have my grid available any more but I do remember that all essential steps in solving the puzzle occured at a time when I was still FAR AWAY from a "BUG" situation. The BUG+1 or BUG+n reasoning only comes into play, when almost all cells in the puzzle are either solved or have only two candidates left.

Looking at the posted grids here, I see a lot of three- four- and even five-candidate cells at the critical points.

Maybe you run that grid with the BUG+1 by us and also how you got there?
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