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daj95376
Joined: 23 Aug 2008 Posts: 3854
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Posted: Thu Jun 10, 2010 11:37 am Post subject: Puzzle 10/06/10: (B) BBDB as VH+ |
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Code: | +-----------------------+
| 9 . . | . . . | 2 . . |
| . 5 3 | . 4 . | 6 . 7 |
| . 6 . | 9 . . | 3 4 . |
|-------+-------+-------|
| . . 7 | 4 . . | . 3 6 |
| . 9 . | . 7 . | . . 4 |
| . . . | . . 9 | . . . |
|-------+-------+-------|
| 6 7 8 | . . . | 4 . . |
| . . 2 | 6 . . | . 8 9 |
| . 4 . | 2 8 . | . 6 . |
+-----------------------+
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Play this puzzle online at the Daily Sudoku site
Code: | after basics
+--------------------------------------------------------------+
| 9 8 4 | 7 36 36 | 2 15 15 |
| 2 5 3 | 18 4 18 | 6 9 7 |
| 7 6 1 | 9 25 25 | 3 4 8 |
|--------------------+--------------------+--------------------|
| 18 12 7 | 4 125 1258 | 9 3 6 |
| 138 9 56 | 138 7 1268 | 158 125 4 |
| 4 123 56 | 138 126 9 | 158 7 125 |
|--------------------+--------------------+--------------------|
| 6 7 8 | 5 9 13 | 4 12 123 |
| 5 13 2 | 6 13 4 | 7 8 9 |
| 13 4 9 | 2 8 7 | 15 6 135 |
+--------------------------------------------------------------+
# 48 eliminations remain
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peterj
Joined: 26 Mar 2010 Posts: 974 Location: London, UK
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Posted: Thu Jun 10, 2010 5:10 pm Post subject: |
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Two steps - with only a very short xy-chain!
Quote: | type 4 UR(25); r4c56<>2
xy-chain (2=6)r5c6-(6=3)r1c6-(3=1)r7c6-(1=2)r7c8; r5c8<>2 |
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tlanglet
Joined: 17 Oct 2007 Posts: 2468 Location: Northern California Foothills
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Posted: Thu Jun 10, 2010 5:51 pm Post subject: |
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This is not a VH+ step, but who can resist a big DP!
6-cell DP15 r159c789 forces r5c7=8, r5c8=2, or r9c9=3 to prevent the deadly pattern.
Code: | (8)r5c7 - ANP(18=3)r45c1 - (3=1)r9c1
(2)r5c8 - (2=1)r7c8 - r9c79 = (1)r9c1
(3)r9c9 - (3=1)r9c1 |
Thus r9c1=1 to complete the puzzle.
However, I am still redoing the puzzle following Danny's guideline of VH+ techniques only and will post my solution later.
Ted |
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Mogulmeister
Joined: 03 May 2007 Posts: 1151
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Posted: Thu Jun 10, 2010 6:06 pm Post subject: |
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One ugly non VH step:
Making use of the strong links on 6s 3s & 2s to create a nasty chain
(12-6)r6c5=r1c5-(6=3)r1c6-r7c6=(3-2)r7c9=r6c9-r5c8=(2-6)r5c6=(6)r6c5 ;
so r6c5=6
If time allows I too will try again...have to look at Ted's extravaganza first ! |
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tlanglet
Joined: 17 Oct 2007 Posts: 2468 Location: Northern California Foothills
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Posted: Thu Jun 10, 2010 6:21 pm Post subject: |
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I found this a very difficult puzzle using VH+ steps only.
Quote: | Type 3 UR25 r34c45: r4c2<>1
skyscraper 1 r8c25; r4c1, r6c4<>1
Kraken x-wing 1 r17c89 with Kraken fin (1)r7c6 - r8c5 = r8c2 - r6c2 = (1)r5c1: r5c8<>1
xy-wing 12-5; r6c7<>5
BUG+1 forces r7c9=1 |
Ted |
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peterj
Joined: 26 Mar 2010 Posts: 974 Location: London, UK
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Posted: Thu Jun 10, 2010 8:30 pm Post subject: |
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Ah! So now I understand the 'BBDB as VH+' designation! I'll have a go too.
Personally I don't think a simple (non-pair, no-almost, not too long) xy-chain is an "advanced" move - but I am happy to stick with the rules. And to be fair Danny does all the work! |
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peterj
Joined: 26 Mar 2010 Posts: 974 Location: London, UK
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Posted: Thu Jun 10, 2010 8:57 pm Post subject: |
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My VH+solution is same as Ted's - but only seemed to need a Finned X-Wing not the Kraken variety...
Quote: | type 4 UR(25); r4c56<>2
skyscraper(1); r4c1<>1
finned x-wing(1) r59c17 fin r6c7; r5c8<>1
xy-wing(125) r7c8; r6c7<>5
BUG+1; r7c9=1 |
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Luke451
Joined: 20 Apr 2008 Posts: 310 Location: Southern Northern California
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Posted: Thu Jun 10, 2010 9:24 pm Post subject: |
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tlanglet wrote: | This is not a VH+ step, but who can resist a big DP!
6-cell DP15 r159c789 forces r5c7=8, r5c8=2, or r9c9=3 to prevent the deadly pattern.
Code: | (8)r5c7 - ANP(18=3)r45c1 - (3=1)r9c1
(2)r5c8 - (2=1)r7c8 - r9c79 = (1)r9c1
(3)r9c9 - (3=1)r9c1 |
Thus r9c1=1 to complete the puzzle.
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I can't resist 'em either, esp if they solve the puzzle!
Still, I don't understand the "ANP" part.
Code: | +--------------------------------------------------------------+
| 9 8 4 | 7 36 36 | 2 15 15 |
| 2 5 3 | 18 4 18 | 6 9 7 |
| 7 6 1 | 9 25 25 | 3 4 8 |
|--------------------+--------------------+--------------------|
| 18 12 7 | 4 125 1258 | 9 3 6 |
| 138 9 56 | 138 7 1268 | 158 125 4 |
| 4 123 56 | 138 126 9 | 158 7 125 |
|--------------------+--------------------+--------------------|
| 6 7 8 | 5 9 13 | 4 12 123 |
| 5 13 2 | 6 13 4 | 7 8 9 |
| 13 4 9 | 2 8 7 | 15 6 135 |
+--------------------------------------------------------------+ |
All I can see is (8)r5c7-(8=13)r59c1, which doesn't lead to (1)r9c1.
How does the ANP thing work here? Maybe my problem is I don't see ANPs, but ALSs.
Edit typo
Last edited by Luke451 on Fri Jun 11, 2010 2:08 pm; edited 1 time in total |
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daj95376
Joined: 23 Aug 2008 Posts: 3854
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Posted: Thu Jun 10, 2010 10:17 pm Post subject: |
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Luke451 wrote: | tlanglet wrote: | This is not a VH+ step, but who can resist a big DP!
6-cell DP15 r159c789 forces r5c7=8, r5c8=2, or r9c9=3 to prevent the deadly pattern.
Code: | (8)r5c7 - ANP(18=3)r45c1 - (3=1)r9c1
(2)r5c8 - (2=1)r7c8 - r9c79 = (1)r9c1
(3)r9c9 - (3=1)r9c1 |
Thus r9c1=1 to complete the puzzle.
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I can't resist 'em either, esp if they solve the puzzle!
Still, I don't understand the "ANP" part.
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I believe the use of the ANP() is incorrect. All r5c7=8 does is the elimination r5c1<>8. This still leaves r4c1=8 and r5c1=1 as possible, thus countering the ANP() claim. |
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tlanglet
Joined: 17 Oct 2007 Posts: 2468 Location: Northern California Foothills
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Posted: Thu Jun 10, 2010 10:41 pm Post subject: |
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I (thought?) I saw this ANP(18=3)r45c1 move on Eureka but never fully understood it; my thinking was the same as Danny's comment. This is the first time I used it, hoping more "informed" folks would speak up if it was incorrect. Thanks Luke and Danny.
Ted |
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daj95376
Joined: 23 Aug 2008 Posts: 3854
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Posted: Thu Jun 10, 2010 10:56 pm Post subject: |
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This puzzle should be rated: BBDB as Advanced !!!
BTW: How about?
(8)r5c7 - r6c7 = (8)r6c4 - ANP(18=3)r25c4 - (3=18)r45c1 - (1)r9c1 ___ Wrong!!!
Last edited by daj95376 on Fri Jun 11, 2010 2:30 pm; edited 1 time in total |
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tlanglet
Joined: 17 Oct 2007 Posts: 2468 Location: Northern California Foothills
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Posted: Thu Jun 10, 2010 11:34 pm Post subject: |
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daj95376 wrote: |
(8)r5c7 - r6c7 = (8)r6c4 - ANP(18=3)r25c4 - (3=18)r45c1 - (1)r9c1 |
Danny, I was just going to look into an alternate step for r5c7=8 since I posted an invalid step previously. Your solution is beautiful!
Ted |
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ronk
Joined: 07 May 2006 Posts: 398
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Posted: Fri Jun 11, 2010 1:43 am Post subject: |
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daj95376 wrote: | BTW: How about?
(8)r5c7 - r6c7 = (8)r6c4 - ANP(18=3)r25c4 - (3=18)r45c1 - (1)r9c1 |
How does an AIC with weak inferences on both ends work?
BTW: No ANP, but how about ...
(3)r7c9 - (3)r7c6 = (3-6)r1c6 = (6-2)r5c6 = (2)r5c8 - (2)r7c8 = (2)r7c9 --> r7c9<>3
BTW2: My "AN[PTQ]" in an earlier post was meant to be taken as a joke. |
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daj95376
Joined: 23 Aug 2008 Posts: 3854
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Posted: Fri Jun 11, 2010 2:03 am Post subject: |
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ronk wrote: | daj95376 wrote: | BTW: How about?
(8)r5c7 - r6c7 = (8)r6c4 - ANP(18=3)r25c4 - (3=18)r45c1 - (1)r9c1 |
How does an AIC with weak inferences on both ends work?
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Ted's post was based on a DP where one of three conditions must be true. He then searched for a common elimination for all three conditions being true. Unfortunately, he had a mistake in the condition r5c7=8. I provided a replacement chain/stream that contained the desired common elimination.
Yes, your chain does a nice job of cracking the puzzle! |
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Luke451
Joined: 20 Apr 2008 Posts: 310 Location: Southern Northern California
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Posted: Fri Jun 11, 2010 2:12 pm Post subject: |
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daj95376 wrote: | This puzzle should be rated: BBDB as Advanced !!!
BTW: How about?
(8)r5c7 - r6c7 = (8)r6c4 - ANP(18=3)r25c4 - (3=18)r45c1 - (1)r9c1 |
Isn't Ted trying to prove r9c1=(1)? |
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daj95376
Joined: 23 Aug 2008 Posts: 3854
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Posted: Fri Jun 11, 2010 2:29 pm Post subject: |
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Luke451 wrote: | Isn't Ted trying to prove r9c1=(1)? |
_ _ _ _ _ _
Thanks Luke!!! Another instance where my eyes crossed!!!
So, that chain/stream is still unfulfilled. |
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Marty R.
Joined: 12 Feb 2006 Posts: 5770 Location: Rochester, NY, USA
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Posted: Sat Jun 12, 2010 5:05 am Post subject: |
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UR (25) with 18 pseudo cell sets r4c2=2
XYZ-Wing (158)
M-Wing (18), slightly convoluted |
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