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December 25, Happy Christmas!

 
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Glassman



Joined: 21 Oct 2005
Posts: 50
Location: England

PostPosted: Sun Dec 25, 2005 7:35 am    Post subject: December 25, Happy Christmas! Reply with quote



Happy Christmas, everyone.

Sam — Thanks for today's 9x9 puzzle. You seem to have saved one of your best for Christmas day. A particularly fine puzzle for sticklers (whether or not fingers are utilised).

It took me considerable time to figure out the trickier bits

Thanks for all your time and effort,

Glassman

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bev
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PostPosted: Mon Dec 26, 2005 2:13 pm    Post subject: Reply with quote

Ok smarty pants, then maybe you can help me. I got stuck as follows:
x367x8xxx
7xxxxx9xx
5xxxxx37x
xxx126754
xx48x72xx
x7xx438xx
x17xxxx92
xx9xxxxxx
xxx6x948x

I went for the hint and it gave me a 9 in row 1, column 5. I can't find a reason why that has to be.

Any ideas?
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Guest






PostPosted: Mon Dec 26, 2005 7:59 pm    Post subject: Reply with quote

I think he was referring to yesterdays puzzle. As far as todays goes,I have r1c5 narrowed down to either 5 or 9. Ill take your hint and finish it off

Heres what I have so far:
x367x8xxx
7xxx3x9x6
5xxx6x378
xxx126754
xx48x72xx
x7xx438xx
x17x8xx92
xx9x72xxx
xxx619487

bev wrote:
Ok smarty pants, then maybe you can help me. I got stuck as follows:
x367x8xxx
7xxxxx9xx
5xxxxx37x
xxx126754
xx48x72xx
x7xx438xx
x17xxxx92
xx9xxxxxx
xxx6x948x

I went for the hint and it gave me a 9 in row 1, column 5. I can't find a reason why that has to be.

Any ideas?
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Guest






PostPosted: Mon Dec 26, 2005 8:15 pm    Post subject: Reply with quote

Solution:




























436798125
728531946
591462378
983126754
164857239
275943861
617384592
849275613
352619487
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someone_somewhere



Joined: 07 Aug 2005
Posts: 275
Location: Munich

PostPosted: Tue Dec 27, 2005 6:49 am    Post subject: Reply with quote

Hi,

I will try to help.
Starting from:
Code:
  . 3 6 7 . 8 . . .
  7 . . . . . 9 . .
  5 . . . . . 3 7 .
  . . . 1 2 6 7 5 4
  . . 4 8 . 7 2 . .
  . 7 . . 4 3 8 . .
  . 1 7 . . . . 9 2
  . . 9 . . . . . .
  . . . 6 . 9 4 8 .

follow the path:
Code:
 3 not in r5c1, it is in r4c1 or r4c3 (Row on 3x3 Block interaction)

 9 not in r5c1, not in r5c2, not in r6c1, it is in r4c1 or r4c2 (Row on 3x3 Block interaction)

 2 not in r8c1, not in r8c2, it is in r9c1 or r9c2 or r9c3 (Row on 3x3 Block interaction)

 6 not in r8c8, not in r8c9, it is in r7c7 or r8c7 (Column on 3x3 Block interaction)

 1 not in r1c1, 1 not in r1c8, 9 not in r1c1, Hidden Pair 2 4 in r1c1 and r1c8 (in Row)

 1 not in r1c5, 5 not in r1c5, Nacked Pair 1 5 in r1c7 and r1c9 (same Row)

 3 not in r9c5, 3 not in r9c9, 5 not in r9c5, 5 not in r9c9, Hidden Pair 1 7 in r9c5 and r9c9 (in Row)

and now we can deduce:
9 in r1c5 - Sole Candidate

see u,
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Bev
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PostPosted: Tue Dec 27, 2005 4:39 pm    Post subject: Reply with quote

I'm starting to feel really stupid here. I can't follow any of your "not"s - for example, WHY can't there be a 3 in row 5 column 1??? There's no 3 in column 1, no 3 in row 5 and no 3 in that 3X3 block. Likewise for the other ones you have said "not in" about. Is there some other logic I am totally missing?
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Bev
Guest





PostPosted: Tue Dec 27, 2005 9:33 pm    Post subject: Reply with quote

OK now I'm seeing the additional logic steps I hadn't thought about before. Got this Xmas puzzle done anyway, and my first very hard one. Still have a lot to learn when it comes to the hidden pairs and triplets though - any rules of thumb on those?
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