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Earl
Joined: 30 May 2007
Posts: 677
Location: Victoria, KS
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 Posted: Tue Jul 03, 2007 3:15 am Post subject: Need Help |
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I could use help on this one.
Thanks
Earl
| Code: |
+---------+-----------+------------+
| 9 7 18 | 18 3 2 | 5 6 4 |
| 6 18 3 | 4 159 15 | 28 29 7 |
| 4 5 2 | 89 7 6 | 38 1 39 |
+---------+-----------+------------+
| 2 16 9 | 7 145 3 | 46 8 56 |
| 7 68 18 | 19 245 45 | 2346 35 39 |
| 3 4 5 | 6 29 8 | 7 29 1 |
+---------+-----------+------------+
| 5 9 47 | 2 146 14 | 36 37 8 |
| 8 2 47 | 3 46 9 | 1 57 56 |
| 1 3 6 | 5 8 7 | 9 4 2 |
+---------+-----------+------------+
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Play this puzzle online at the Daily Sudoku site |
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jLo
Joined: 30 Apr 2007
Posts: 55
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| Posted: Tue Jul 03, 2007 5:10 am Post subject: |
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After a W-wing with the 46's
a W-wing with the resulting 15's
a couple of X-wings on 1s
an X-wing on 9s
You end up here
| Code: |
+---------+---------+-----------+
| 18 | 18 | |
| 18 | 19 | 28 29 |
| | 89 | 38 39 |
+---------+---------+-----------+
| 16 | 15 | 56 |
| 68 18 | 19 25 | 236 35 39 |
| | 29 | 29 |
+---------+---------+-----------+
| 47 | 46 | 36 37 |
| 47 | 46 | 57 56 |
| | | |
+---------+---------+-----------+
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From here I started coloring with R1C3 and ended up solving R5c7 which, pretty much
finished it off. |
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Earl
Joined: 30 May 2007
Posts: 677
Location: Victoria, KS
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| Posted: Tue Jul 03, 2007 1:30 pm Post subject: need help |
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jLo,
Thanks,
Is the grid you posted a BUG yielding a 3 in R5C7?
Earl |
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jLo
Joined: 30 Apr 2007
Posts: 55
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| Posted: Tue Jul 03, 2007 3:03 pm Post subject: |
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| Quote: |
Is the grid you posted a BUG yielding a 3 in R5C7?
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I hadn't noticed that, but yes it is. |
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Asellus
Joined: 05 Jun 2007
Posts: 865
Location: Sonoma County, CA, USA
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| Posted: Tue Jul 03, 2007 6:38 pm Post subject: |
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jLo's first W-Wing is also an XY-Chain.
There is another XY-Chain with pincers at R5C2 and R4C9 that eliminates <6> from R5C7.
These two XY-Chains solve the puzzle.
Nice to see the BUG+1! |
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Earl
Joined: 30 May 2007
Posts: 677
Location: Victoria, KS
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| Posted: Tue Jul 03, 2007 8:03 pm Post subject: Need Help |
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Asselius,
What is the difference between an "xy-chain" and an xy-wing"
Please explain slowly. I am a novice.
Thanks,
Earl |
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Mogulmeister
Joined: 03 May 2007
Posts: 1151
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jLo
Joined: 30 Apr 2007
Posts: 55
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| Posted: Wed Jul 04, 2007 5:26 am Post subject: |
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| Quote: |
jLo's first W-Wing is also an XY-Chain.
There is another XY-Chain with pincers at R5C2 and R4C9 that eliminates <6> from R5C7.
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I don't see either of these chains. Can you give me the long version? |
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TKiel
Joined: 22 Feb 2006
Posts: 292
Location: Kalamazoo, MI
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| Posted: Wed Jul 04, 2007 11:50 am Post subject: |
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| jLo wrote: | | I don't see either of these chains. Can you give me the long version? |
Not sure if this is the exact chain that Asellus used:
| Code: |
*-----------------------------------------------------------*
| 9 7 18c | 18d 3 2 | 5 6 4 |
| 6 18b 3 | 4 159 15 | 28 29 7 |
| 4 5 2 | 89 7 6 | 38 1 39 |
|-------------------+-------------------+-------------------|
| 2 16 9 | 7 145 3 | 46 8 56j |
| 7 68a 18 | 19e 245 45 | 2346 35i 39h |
| 3 4 5 | 6 29f 8 | 7 29g 1 |
|-------------------+-------------------+-------------------|
| 5 9 47 | 2 146 14 | 36 37 8 |
| 8 2 47 | 3 46 9 | 1 57 56 |
| 1 3 6 | 5 8 7 | 9 4 2 |
*-----------------------------------------------------------*
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R5c2 shares <8> with r2c2, which leaves the <6> dangling. Now use the leftover digit in r2c2 <1> to link with another cell, in this case r1c3. The leftover digit there <8> links with r1c4. The chain is constructed in this manner, always alternating links, until another cell that has a <6> dangling is reached. When the two cells on the end of the chain have the same dangling digit and can both see a third cell that contains that digit, that digit can be eliminated from the third cell. In this case, the <6> in r5c7 and r4c2 can be eliminated. |
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jLo
Joined: 30 Apr 2007
Posts: 55
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| Posted: Wed Jul 04, 2007 1:21 pm Post subject: |
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| Quote: |
Not sure if this is the exact chain that Asellus used:
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OK, I see that one, but what about one that
links the 46 at R8C5 with the 46 at R4C7? That's
how I interpreted the post that said the W-wing
was also an XY-chain. Since the W-wing eliminates
a 4 at R4C5, the end's of the XY-chain would have
to be a 4 to do the same elimination. The partner
value of the 4 at R4C7 is a 6 which appears three
times in each row, column, and block that R4C7
is part of, which makes in un-linkable from my view. |
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ravel
Joined: 21 Apr 2006
Posts: 536
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| Posted: Wed Jul 04, 2007 5:26 pm Post subject: |
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| jLo wrote: | OK, I see that one, but what about one that
links the 46 at R8C5 with the 46 at R4C7? |
| Code: | *-------------------------------------------*
| 9 7 18 | 18 3 2 | 5 6 4 |
| 6 18 3 | 4 159 15 | 28 29 7 |
| 4 5 2 | 89 7 6 | 38 1 39 |
|------------+--------------+---------------|
| 2 16 9 | 7 145 3 |#46 8 56 |
| 7 68 18 | 19 245 45 | 2346 35 39 |
| 3 4 5 | 6 29 8 | 7 29 1 |
|------------+--------------+---------------|
| 5 9 47 | 2 146 14 |#36 #37 8 |
| 8 2 47 | 3 #46 9 | 1 #57 #56 |
| 1 3 6 | 5 8 7 | 9 4 2 |
*-------------------------------------------*
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Either r4c7=4
or (r4c7=6 => r7c7=3 => r7c8=7 => r8c8=5 => r8c9=6 =>) r8c5=4
=> r4c5<>4 | Code: | *------------------------------------------*
| 9 7 18 | 18 3 2 | 5 6 4 |
| 6 #18 3 | 4 159 #15 | 28 29 7 |
| 4 5 2 | 89 7 6 | 38 1 39 |
|------------+--------------+--------------|
| 2 #16 9 | 7 #15 3 | 4 8 56 |
| 7 #68 18 | 19 245 45 | 236 35 39 |
| 3 4 5 | 6 29 8 | 7 29 1 |
|------------+--------------+--------------|
| 5 9 47 | 2 146 14 | 36 37 8 |
| 8 2 47 | 3 46 9 | 1 57 56 |
| 1 3 6 | 5 8 7 | 9 4 2 |
*------------------------------------------*
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Here there is an xy-wing (pivot r5c6), that eliminates 1 in r7c5, which leads to the BUG grid.
Or another xy-chain to eliminate 5 in r2c5:
Either r2c6=5
or (r2c6=1 => r2c2=8 => r5c2=6 => r4c2=1 =>) r4c5=5 |
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