| View previous topic :: View next topic |
| Author |
Message |
Earl
Joined: 30 May 2007
Posts: 677
Location: Victoria, KS
|
 Posted: Sun Nov 01, 2009 2:55 am Post subject: Nov 1 VH |
 |
|
Very Strange. A Halloween trick?
Consecutive VH's with same solution?
Solution: 168 xy-wing
Early Earl |
|
| Back to top |
|
 |
pw
Joined: 02 Jan 2009
Posts: 3
|
| Posted: Sun Nov 01, 2009 4:59 pm Post subject: I don't see it- |
|
|
| Earl- I must have some type of mental block; I don't see the XY wing on this one. can you give me the three cells (r,c) that you use to produce the first XY wing of 168? Maybe I don't understand XY wing well enough, but I think: A) I'm looking for three separate cells, B) each pair shares a number, or candidate, C) each of the three shared numbers are unique (don't use the same one twice), and D) each of the three cells has only two candidates. Are those assumptions correct? Thanks. pw |
|
| Back to top |
|
|
wapati
Joined: 10 Jun 2008
Posts: 472
Location: Brampton, Ontario, Canada.
|
| Posted: Sun Nov 01, 2009 5:25 pm Post subject: |
|
|
Are you doing the October 31st puzzle?
| Code: | . . .|. . 1|. 4 .
3 . 8|. . .|7 . 9
5 . .|2 . .|. . 8
-----+-----+-----
. . .|3 2 7|5 . .
. . 2|. . .|9 . .
. . 3|9 5 6|. . .
-----+-----+-----
2 . .|. . 5|. . 4
8 . 7|. . .|1 . 3
. 4 .|7 . .|. . . |
There are two 168 xy-wings.
| Code: | .---------------.---------------.---------------.
| 9 7 6 | 8 3 1 | 2 4 5 |
| 3 2 8 | 5 6 4 | 7 1 9 |
| 5 1 4 | 2 7 9 | 3 6 8 |
:---------------+---------------+---------------:
| 4 69 19 | 3 2 7 | 5 8 16 |
| 67 5 2 | 14 14 8 | 9 3 67 |
| 17 8 3 | 9 5 6 | 4 2 17 |
:---------------+---------------+---------------:
| 2 3 19 |#16 19-8 5 |#68 7 4 |
| 8 69 7 | 46 49 2 | 1 5 3 |
| 16 4 5 | 7 #18 3 | 6-8 9 2 |
'---------------'---------------'---------------'
.---------------.---------------.---------------.
| 9 7 6 | 8 3 1 | 2 4 5 |
| 3 2 8 | 5 6 4 | 7 1 9 |
| 5 1 4 | 2 7 9 | 3 6 8 |
:---------------+---------------+---------------:
| 4 69 19 | 3 2 7 | 5 8 16 |
| 67 5 2 | 14 14 8 | 9 3 67 |
| 17 8 3 | 9 5 6 | 4 2 17 |
:---------------+---------------+---------------:
| 2 3 19 |#16 189 5 | 8-6 7 4 |
| 8 69 7 | 46 49 2 | 1 5 3 |
| 16 4 5 | 7 #18 3 |#68 9 2 |
'---------------'---------------'---------------' |
There is also an xyz wing.
| Code: | .---------------.---------------.---------------.
| 9 7 6 | 8 3 1 | 2 4 5 |
| 3 2 8 | 5 6 4 | 7 1 9 |
| 5 1 4 | 2 7 9 | 3 6 8 |
:---------------+---------------+---------------:
| 4 69 19 | 3 2 7 | 5 8 16 |
| 67 5 2 | 14 14 8 | 9 3 67 |
| 17 8 3 | 9 5 6 | 4 2 17 |
:---------------+---------------+---------------:
| 2 3 #19 | 6-1 #189 5 | 68 7 4 |
| 8 69 7 | 46 49 2 | 1 5 3 |
| 16 4 5 | 7 #18 3 | 68 9 2 |
'---------------'---------------'---------------' |
This is the November 1st one.
| Code: | 4 1 .|. . 7|. 8 .
7 . 3|. . 9|. . .
. 2 9|. 4 5|3 . .
-----+-----+-----
. . .|. . 2|4 . 8
. . .|. . .|. . .
2 . 6|7 . .|. . .
-----+-----+-----
. . 1|5 7 .|6 9 .
. . .|9 . .|8 . 7
. 7 .|6 . .|. 4 5 |
Check r3c1 r3c4 r2c5 or r2c2 r2c5 r3c4. |
|
| Back to top |
|
|
Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
|
| Posted: Sun Nov 01, 2009 6:19 pm Post subject: |
|
|
PW, welcome to the forum.
To put the XY-Wing into the form of a rule:
Start with a two-candidate cell we'll call XY. That cell must see both an XZ cell and a YZ cell. Any cells that see both XZ and YZ cannot contain Z.
Example, not from this puzzle.
XY = 49
XZ = 42
YZ = 92
The 2 is eliminated from any cell that sees both the 42 and 92. |
|
| Back to top |
|
|
pw
Joined: 02 Jan 2009
Posts: 3
|
| Posted: Mon Nov 02, 2009 2:35 am Post subject: still trying... |
|
|
Hi wapati and Marty R.,
Thanks for the reply. I am working on Nov 1 (not 10/31). At this point I still have three candidates in r2c5 (1,6, and 8).
That's my issue- I can't use r2c5 as part of an XY wing, right? Maybe I'm not far enough along. Marty, your explanation
confirms my assumption about XY wings. I have r3c1=6,8 r3c4=1,8 and r2c2=6,8 (plus the aforementioned r2c5=1,6,8)
Doesn't look like I have three cells with three unique pairs. I must have to eliminate something besides the "1" from r2c5 ?
Still not there. Thanks- pw
(Edited by Marty to disable smilies) |
|
| Back to top |
|
|
Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
|
| Posted: Mon Nov 02, 2009 4:53 am Post subject: |
|
|
This is what you said you had:
| Code: |
+---------+----------+-------+
| . . . | . . . | . . . |
| . 68 . | . 168 . | . . . |
| 68 . . | 18 . . | . . . |
+---------+----------+-------+
| . . . | . . . | . . . |
| . . . | . . . | . . . |
| . . . | . . . | . . . |
+---------+----------+-------+
| . . . | . . . | . . . |
| . . . | . . . | . . . |
| . . . | . . . | . . . |
+---------+----------+-------+
|
Play this puzzle online at the Daily Sudoku site
You don't have an XY-Wing there, but you would have two if the 8 were gone from r2c5. However, you do have an XYZ-Wing (168-18-68) which would eliminate 8s from r2c4 and r2c6. |
|
| Back to top |
|
|
pw
Joined: 02 Jan 2009
Posts: 3
|
| Posted: Mon Nov 02, 2009 2:45 pm Post subject: thanks- |
|
|
Hi Marty,
You captured my text correctly in your diagram. I guess what I can't reconcile is that Earl called it an XY wing, but I can't get to the point where an XY wing would work. Only XYZ as you pointed out. Time to move on, I guess. Thanks for your responsiveness and help. pw |
|
| Back to top |
|
|
Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
|
| Posted: Mon Nov 02, 2009 5:47 pm Post subject: |
|
|
PW,
I was monkeying around with this puzzle online and in the middle of basics when I found myself here:
| Code: |
+-------------+---------------+----------------+
| 4 1 5 | 23 36 7 | 29 8 69 |
| 7 68 3 | 128 16 9 | 25 1256 4 |
| 68 2 9 | 18 4 5 | 3 7 16 |
+-------------+---------------+----------------+
| 135 359 7 | 13 13569 2 | 4 156 8 |
| 135 359 8 | 4 13569 136 | 2579 1256 1369 |
| 2 3459 6 | 7 13589 138 | 59 15 139 |
+-------------+---------------+----------------+
| 38 348 1 | 5 7 48 | 6 9 2 |
| 56 456 24 | 9 12 14 | 8 3 7 |
| 9 7 2 | 6 238 38 | 1 4 5 |
+-------------+---------------+----------------+
|
Play this puzzle online at the Daily Sudoku site
Look at column 4. Note that 2 and 8 have to be in box 2, therefore, those two numbers must be removed from other columns in that box, thus exposing the XY-Wing. Could that be where you got stuck? |
|
| Back to top |
|
|
|
|
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
|
Powered by phpBB © 2001, 2005 phpBB Group
|
FAQ
Search
Memberlist
Usergroups
Register
Profile
Log in to check your private messages
Log in
