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storm_norm
Joined: 18 Oct 2007 Posts: 1741
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Posted: Tue Nov 25, 2008 9:53 pm Post subject: 11-25 vanhegan fiendish |
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Code: |
+-------+-------+-------+
| 5 2 4 | 6 . . | . 8 . |
| 1 9 . | . 5 . | . . 6 |
| . . . | . . . | . . . |
+-------+-------+-------+
| . . . | 4 . . | . 6 7 |
| 9 . . | 1 . 6 | . . 4 |
| 4 8 . | . . 3 | . . . |
+-------+-------+-------+
| . . . | . . . | . . . |
| 8 . . | . 6 . | . 1 9 |
| . 6 . | . . 8 | 2 7 5 |
+-------+-------+-------+
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Play this puzzle online at the Daily Sudoku site
Code: | .------------------.------------------.------------------.
| 5 2 4 | 6 1379 179 | 179 8 13 |
| 1 9 38 | 38 5 247 | 47 24 6 |
| 6 37 378 | 238 1239 1249 | 1459 2459 123 |
:------------------+------------------+------------------:
| 2 1 35 | 4 89 59 | 3589 6 7 |
| 9 37 357 | 1 28 6 | 358 235 4 |
| 4 8 6 | 257 279 3 | 159 259 12 |
:------------------+------------------+------------------:
| 7 45 9 | 235 123 125 | 6 34 8 |
| 8 45 2 | 357 6 57 | 34 1 9 |
| 3 6 1 | 9 4 8 | 2 7 5 |
'------------------'------------------'------------------' |
two syllables - UGH ! LEE !
Quote: |
swordfish on 3; r35c3, r37c4, r5c7 are all not 3.
m-wing {5,7} (5=7)r8c6 - (7)r8c4 = (7-5)r6c4 = (5)r4c6; r7c6 <> 5
this opens up this beast of a chain.
(1=2)r7c6 - (2=5)r7c4 - (5)r6c4 = (5)r4c6 - (5=3)r4c3 - (3)r2c3 = (3)r2c4 - (3)r8c4 = (3)r7c5; r7c5 <> 1 |
Last edited by storm_norm on Wed Nov 26, 2008 3:27 am; edited 1 time in total |
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re'born
Joined: 28 Oct 2007 Posts: 80
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Posted: Tue Nov 25, 2008 10:10 pm Post subject: |
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Extend an xyz-wing a little and transport:
Code: |
*-----------------------------------------------------------*
| 5 2 4 | 6 1379 179 | 179 8 13 |
| 1 9 +38 |+38 5 247 | 47 24 6 |
| 6 37 378 | 238 1239 1249 | 1459 2459 123 |
|-------------------+-------------------+-------------------|
| 2 1 *35 | 4 89 %59 | 3589 6 7 |
| 9 37 357 | 1 28 6 | 358 235 4 |
| 4 8 6 |%257 279 3 | 159 259 12 |
|-------------------+-------------------+-------------------|
| 7 45 9 | 23-5 123 125 | 6 34 8 |
| 8 45 2 |*357 6 *57 | 34 1 9 |
| 3 6 1 | 9 4 8 | 2 7 5 |
*-----------------------------------------------------------*
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The extended xyz-wing with pivot at r8c4 and pincers at r8c6 and r4c3 implies one of the endpoints is a 5. Transport the 5 from r4c3 to r6c4 via r4c6. This gives the deduction r7c4<>5, cracking the puzzle. |
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storm_norm
Joined: 18 Oct 2007 Posts: 1741
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Posted: Tue Nov 25, 2008 10:59 pm Post subject: |
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Quote: | This gives the deduction r7c4<>5, cracking the puzzle. |
"impressive. most impressive. OBI WAN has taught you well."
its moves like this where you can imagine the puzzle making that cracking sound. like bowling a strike and listening for the pins "crack" as they all fall down. |
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keith
Joined: 19 Sep 2005 Posts: 3355 Location: near Detroit, Michigan, USA
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Posted: Tue Nov 25, 2008 11:28 pm Post subject: |
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re'born,
Quote: | The extended xyz-wing with pivot at r8c4 and pincers at r8c6 and r4c3 implies one of the endpoints is a 5. |
I think you should add the strong link on <3> in R2 that extends the wing. If R8C4 is <3>, how do you show that R4C3 is <5>?
35* - 38 = 38 - 357* - 57*
And, I think that one of the * cells is <5>, not one of the endpoints.
(Who was it that was counting the ways to extend a wing?)
Keith |
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storm_norm
Joined: 18 Oct 2007 Posts: 1741
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Posted: Wed Nov 26, 2008 5:28 am Post subject: |
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Code: | .------------------.------------------.------------------.
| 5 2 4 | 6 1379 179 | 179 8 13 |
| 1 9 *38 |*38 5 247 | 47 24 6 |
| 6 37 378 | 238 1239 1249 | 1459 2459 123 |
:------------------+------------------+------------------:
| 2 1 *35 | 4 89 *59 | 3589 6 7 |
| 9 37 357 | 1 28 6 | 358 235 4 |
| 4 8 6 |*257 279 3 | 159 259 12 |
:------------------+------------------+------------------:
| 7 *45 9 |23-5 123 125 | 6 34 8 |
| 8 *45 2 |*357 6 *57 | 34 1 9 |
| 3 6 1 | 9 4 8 | 2 7 5 |
'------------------'------------------'------------------' |
could also look like this
(5)r6c4 = (5)r4c6 - (5=3)r4c3 - (3)r2c3 = (3)r2c4 - (3)r8c4 = np(57)r8c46 - (5)r8c2 = (5)r7c2; r7c4 <> 5 |
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nataraj
Joined: 03 Aug 2007 Posts: 1048 Location: near Vienna, Austria
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Posted: Wed Nov 26, 2008 1:18 pm Post subject: |
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I don't find this puzzle ugly at all, at least not if one likes a few challenges.
I'm with Norm through coloring (I'll add a skyscraper (2)) and, before reaching the m-wing, there is a 38 UR type 4 makes r3c34<>3.
Now the m-wing, here: (5)r8c6=r4c6 (via SL (7) col 4); r7c6<>5
Code: |
+--------------------------+--------------------------+--------------------------+
| 5 2 4 | 6 1379 179 | 179 8 13 |
| 1 9 38 | 38 5 247 | 47 24 6 |
| 6 37 78 | 28 139 1249 | 1459 2459 123 |
+--------------------------+--------------------------+--------------------------+
| 2 1 35 | 4 89 59* | 3589 6 7 |
| 9 37 57 | 1 28 6 | 58 235 4 |
| 4 8 6 | 257# 279 3 | 159 259 12 |
+--------------------------+--------------------------+--------------------------+
| 7 45 9 | 25 123 12-5 | 6 34 8 |
| 8 45 2 | 357# 6 57* | 34 1 9 |
| 3 6 1 | 9 4 8 | 2 7 5 |
+--------------------------+--------------------------+--------------------------+
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Thanks to re'born's suggestion a few days ago, I'm trying to make a habit of checking for additional possibilities, when an m-wing begins and ends in the same house (col 6 here) and thus creates a continuous loop.
No 7s can be removed from row 8 or box 8, but
2 can be removed from r6c4.
That leads to this position:
Code: |
+--------------------------+--------------------------+--------------------------+
| 5 2 4 | 6 1379 179 | 179 8 13 |
| 1 9 38* | 38 5 247 | 47 24 6 |
| 6 37 78# | 28 139 1249 | 1459 2459 123 |
+--------------------------+--------------------------+--------------------------+
| 2 1 35* | 4 89* 59 | 3589* 6 7 |
| 9 37 57# | 1 28 6 | 58# 235 4 |
| 4 8 6 | 57 279 3 | 159 259 12 |
+--------------------------+--------------------------+--------------------------+
| 7 45 9 | 25 13 12 | 6 34 8 |
| 8 45 2 | 357 6 57 | 34 1 9 |
| 3 6 1 | 9 4 8 | 2 7 5 |
+--------------------------+--------------------------+--------------------------+
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The useless m-wing *:(8)r4c5=r2c3 (via SL 3 in row 4) and
the useless xy-wing #:(8)r3c3=r5c7 (78-57-58)
can be combined (r2c3 sees r3c3):
(8)r4c5=r2c3-r3c3=r5c7; r4c7,r5c5<>8
With r5c5=2 (and 2 gone from r5c7), we have a useless xy-wing (8)r7c2=r5c8 (35-34-45) that can be transported further to give r7c4<>5 and r8c2<>5.
Code: |
+--------------------------+--------------------------+--------------------------+
| 5 2 4 | 6 1379 179 | 179 8 13 |
| 1 9 38 | 38 5 247 | 47 24 6 |
| 6 37 78 | 28 139 1249 | 1459 2459 123 |
+--------------------------+--------------------------+--------------------------+
| 2 1 35t | 4 8 59t | 359 6 7 |
| 9 37 57t | 1 2 6 | 8 35* 4 |
| 4 8 6 | 57t2 79 3 | 159 259 12 |
+--------------------------+--------------------------+--------------------------+
| 7 45* 9 | 2-5 13 12 | 6 34* 8 |
| 8 4-5 2 | 357 6 57t1 | 34 1 9 |
| 3 6 1 | 9 4 8 | 2 7 5 |
+--------------------------+--------------------------+--------------------------+
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With all the additional diagonal strong links from xy- and other "useless" wings, my diagrams are starting to look very exotic ... :) |
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Asellus
Joined: 05 Jun 2007 Posts: 865 Location: Sonoma County, CA, USA
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Posted: Wed Nov 26, 2008 8:58 pm Post subject: |
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storm_norm wrote: | could also look like this
(5)r6c4 = (5)r4c6 - (5=3)r4c3 - (3)r2c3 = (3)r2c4 - (3)r8c4 = np(57)r8c46 - (5)r8c2 = (5)r7c2; r7c4 <> 5 |
re'born's elimination is more exactly notated this way:
(5)r7c4 - (5)r6c4=(5)r4c6 - (5=3)r4c3 - (3)r2c3=(3)r2c4 - ALS[(3)r8c4=(5)r8c46] - (5)r7c4; r7c4 <> 5
No detour through box 7 is needed. |
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re'born
Joined: 28 Oct 2007 Posts: 80
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Posted: Wed Nov 26, 2008 11:39 pm Post subject: |
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keith wrote: | re'born,
Quote: | The extended xyz-wing with pivot at r8c4 and pincers at r8c6 and r4c3 implies one of the endpoints is a 5. |
I think you should add the strong link on <3> in R2 that extends the wing. If R8C4 is <3>, how do you show that R4C3 is <5>?
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Asellus wrote: |
re'born's elimination is more exactly notated this way:
(5)r7c4 - (5)r6c4=(5)r4c6 - (5=3)r4c3 - (3)r2c3=(3)r2c4 - ALS[(3)r8c4=(5)r8c46] - (5)r7c4; r7c4 <> 5
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The only difference in the way I thought about it was I didn't rely explicitly on the strong link on 3 in row 2. I followed it like an xy-chain. In my head I was saying "357 sees 57 and 38 which sees 83 which sees 35...okay, xyz-wing on 5."
I find the xy-chain way of extending xyz-wings to be less exhaustive a search, but also less exhausting. |
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