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daj95376
Joined: 23 Aug 2008
Posts: 3854
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 Posted: Wed Jun 08, 2011 3:46 pm Post subject: Puzzle 11/06/08: ~ XY (BBDB?) |
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| Code: | +-----------------------+
| . 9 . | . 7 . | 2 8 . |
| 8 . . | . . 2 | . . . |
| . . 4 | . . 8 | 3 7 . |
|-------+-------+-------|
| . . . | 7 . . | 1 . . |
| 2 . . | . 8 1 | . . 4 |
| . 1 9 | . 4 6 | . . . |
|-------+-------+-------|
| 9 . 1 | 6 . . | . 4 8 |
| 6 . 2 | . . . | 9 . . |
| . . . | . 9 . | 6 . 3 |
+-----------------------+
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Play this puzzle online at the Daily Sudoku site |
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peterj
Joined: 26 Mar 2010
Posts: 974
Location: London, UK
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| Posted: Thu Jun 09, 2011 8:01 am Post subject: |
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Two steps - the second a neat als move (I think)
| Quote: | w-wing(51) ; (5=1)r3c1 - r3c5=r2c5 - (1=5)r2c8 ; r2c23<>5, r3c9<>5
hp(15)r13c1=(5)r1c3 - (5=3)r1c6 ; r1c1<>3
... some might prefer the naked triple(367) ... |
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tlanglet
Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills
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| Posted: Thu Jun 09, 2011 2:29 pm Post subject: |
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An anp() that makes two distinct deletions by continuing the chain; both deletions are required to complete the puzzle in one step.
anp(15=3)r13c1-(3=5)r1c6*-r789c6=r8c5-r8c89=r7c7-r5c7=(5)r6c9; r1c3*, r6c1<>5
Ted |
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tlanglet
Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills
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| Posted: Thu Jun 09, 2011 2:38 pm Post subject: |
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| peterj wrote: | Two steps - the second a neat als move (I think)
| Quote: | w-wing(51) ; (5=1)r3c1 - r3c5=r2c5 - (1=5)r2c8 ; r2c23<>5, r3c9<>5
hp(15)r13c1=(5)r1c3 - (5=3)r1c6 ; r1c1<>3
... some might prefer the naked triple(367) ... |
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Peter, Interesting that we both viewed the same pattern thru different glasses. I was specifically looking for anp()s, and being methodical, I started looking in box 1 where I hit the jackpot.
And yes, the als was "neat"...........
Ted |
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dejsmith
Joined: 23 Oct 2005
Posts: 42
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| Posted: Thu Jun 09, 2011 8:22 pm Post subject: |
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Where's Marty? Documenting these alternative solutions stresses me out! Don't worry, though, I'll fall a couple of days behind soon.
1. Coloring on 7: r8c2<>7 (not needed, just 1st thing I saw)
2. Same W Wing as Peter with same eliminations
3. X Wing on 3 r25; r14c3<>3
4. XYZ Wing 135; r1c3<>5
Dave |
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daj95376
Joined: 23 Aug 2008
Posts: 3854
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| Posted: Thu Jun 09, 2011 11:12 pm Post subject: |
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Hmmm!!! I guess that I'm the only one who doesn't see Peter's ALS move.
| Code: | +--------------------------------------------------------------+
| 15+3 9 356 | 4 7 35 | 2 8 156 |
| 8 67 367 | 359 16 2 | 4 15 1569 |
| 15 2 4 | 59 16 8 | 3 7 169 |
|--------------------+--------------------+--------------------|
| 345 458 358 | 7 35 9 | 1 6 2 |
| 2 567 3567 | 35 8 1 | 57 9 4 |
| 57 1 9 | 2 4 6 | 8 3 57 |
|--------------------+--------------------+--------------------|
| 9 357 1 | 6 2 357 | 57 4 8 |
| 6 3457 2 | 8 35 3457 | 9 15 157 |
| 457 4578 578 | 1 9 457 | 6 2 3 |
+--------------------------------------------------------------+
# 62 eliminations remain
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I see: (15)r13c1=(3)r1c1
I don't see: (15)r13c1=(5)r1c3 because r1c1=3 and r3c1=5 force the left side false but not the right side true.
Ted: Nice chain, but it has a shorter cousin.
anp(15=3)r13c1-(3=5)r1c6*-r789c6=r8c5-r4c5=(5)r4c123; r1c3*, r6c1<>5
Upon reviewing my solver's solution, I had no idea that the XYZ-Wing and W-Wing were all that's necessary to crack this puzzle. |
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Luke451
Joined: 20 Apr 2008
Posts: 310
Location: Southern Northern California
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| Posted: Fri Jun 10, 2011 12:37 am Post subject: |
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| daj95376 wrote: | | Hmmm!!! I guess that I'm the only one who doesn't see Peter's ALS move. |
Peter called it an ALS but notated it as a hidden pair. With the 1s conjugate it seems hp(15)r13c1=(5)r1c3 is a valid statement. |
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ronk
Joined: 07 May 2006
Posts: 398
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| Posted: Fri Jun 10, 2011 12:58 am Post subject: |
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| daj95376 wrote: | | Hmmm!!! I guess that I'm the only one who doesn't see Peter's ALS move. |
Did you let the "ALS" mislead you? It's actually an AHS. |
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daj95376
Joined: 23 Aug 2008
Posts: 3854
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| Posted: Fri Jun 10, 2011 5:04 am Post subject: |
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I prefer to have the conjugate on <1> spelled out.
(15=13)r31c1 - (3=5)r1c5 - (5)r1c13 = (5)r3c1 - (13=15)r13c1 => r1c3,r469c1<>5 , r1c1<>3 |
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peterj
Joined: 26 Mar 2010
Posts: 974
Location: London, UK
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| Posted: Fri Jun 10, 2011 7:12 am Post subject: |
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Apologies for the confusion. 
Though I almost wrote it for effect as... 
| Code: | | hp(15)r13c1=np(35)r1c36 |
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ronk
Joined: 07 May 2006
Posts: 398
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| Posted: Fri Jun 10, 2011 12:09 pm Post subject: |
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| daj95376 wrote: | I prefer to have the conjugate on <1> spelled out.
(15=13)r31c1 - (3=5)r1c5 - (5)r1c13 = (5)r3c1 - (13=15)r13c1 => r1c3,r469c1<>5 , r1c1<>3 |
Notation of hidden sets has always been a bit awkward IMO, but cells appearing three times is a new record.
Unless the size of the AHS is much smaller than the complementary ALS, I prefer using the ALS: (3=5)r1c6 - (5=673)r1c3,r2c23 ==> r1c1<>3 |
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daj95376
Joined: 23 Aug 2008
Posts: 3854
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| Posted: Fri Jun 10, 2011 3:55 pm Post subject: |
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Peter, no need for apologies. As Ron just said, "Notation of hidden sets has always been a bit awkward IMO". Since I've been bitten before on the notation, I was sensitive about being caught off balance again.
I agree that my solution sucks! _  _
Ron, how about: (it uses the conjugate on <1>)
(3=5)r1c5 - (5)r1c13 = (5-1)r3c1 = (1)r1c1 => r1c1<>3
This gets around reading Peter's chain from r-to-l and performing -(5)r1c3 instead of -(5)r1c13.
Regards, Danny |
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Luke451
Joined: 20 Apr 2008
Posts: 310
Location: Southern Northern California
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| Posted: Fri Jun 10, 2011 4:18 pm Post subject: |
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| ronk wrote: | | Unless the size of the AHS is much smaller than the complementary ALS, I prefer using the ALS: (3=5)r1c6 - (5=673)r1c3,r2c23 ==> r1c1<>3 |
Seems that all along we've been looking at an ALS-xz  .
| Code: | +--------------------------------------------------------------+
| 153 9 356 | 4 7 35 | 2 8 156 |
| 8 67 367 | 359 16 2 | 4 15 1569 |
| 15 2 4 | 59 16 8 | 3 7 169 |
|--------------------+--------------------+--------------------|
| 345 458 358 | 7 35 9 | 1 6 2 |
| 2 567 3567 | 35 8 1 | 57 9 4 |
| 57 1 9 | 2 4 6 | 8 3 57 |
|--------------------+--------------------+--------------------|
| 9 357 1 | 6 2 357 | 57 4 8 |
| 6 3457 2 | 8 35 3457 | 9 15 157 |
| 457 4578 578 | 1 9 457 | 6 2 3 |
+--------------------------------------------------------------+ |
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Sat Jun 11, 2011 4:20 am Post subject: |
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| Quote: | | Upon reviewing my solver's solution, I had no idea that the XYZ-Wing and W-Wing were all that's necessary to crack this puzzle. |
That's what I did, the W-Wing followed by the XYZ-Wing. |
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