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daj95376
Joined: 23 Aug 2008 Posts: 3854
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Posted: Wed Apr 07, 2010 5:03 pm Post subject: Puzzle 10/04/07 (B) |
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Hard VH+ ?
Code: | +-----------------------+
| 1 . 6 | . . 4 | 9 5 . |
| . 8 5 | . . 9 | . . 6 |
| 9 4 . | 6 5 . | . 2 . |
|-------+-------+-------|
| . . 3 | 2 . . | . 6 . |
| . . 4 | . 3 . | . . . |
| 8 6 . | . . 5 | . . . |
|-------+-------+-------|
| 6 . . | . . . | . . 3 |
| 4 . 8 | 5 . . | . . 2 |
| . 3 . | . . . | 6 9 5 |
+-----------------------+
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Play this puzzle online at the Daily Sudoku site |
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Mogulmeister
Joined: 03 May 2007 Posts: 1151
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Posted: Wed Apr 07, 2010 6:02 pm Post subject: |
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This was a doozie because I went looking at chains and then decided on a different tack altogether !
Quote: | 1. UR in blocks 7 and 8 on <12> eliminating 1s in r79c6
2.A "skinny" finned swordfish on 1s in r269 eliminating 1s inR4C7 R5C8 |
Very Entertaining!! |
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daj95376
Joined: 23 Aug 2008 Posts: 3854
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Posted: Wed Apr 07, 2010 10:18 pm Post subject: |
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In my solution for this puzzle, there seems to be a critical combination of initial steps for it to qualify as VH+. |
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tlanglet
Joined: 17 Oct 2007 Posts: 2468 Location: Northern California Foothills
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Posted: Thu Apr 08, 2010 3:32 am Post subject: |
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Fun puzzle!
Code: |
*-----------------------------------------------------------*
| 1 2 6 | 3 78 4 | 9 5 78 |
| 3 8 5 | 17 2 9 | 147 147 6 |
| 9 4 7 | 6 5 18 | 3 2 18 |
|-------------------+-------------------+-------------------|
| 5 17 3 | 2 49 178 | 178 6 49 |
| 2 17 4 | 1789 3 6 | 5 178 179 |
| 8 6 9 | 147 147 5 | 2 3 147 |
|-------------------+-------------------+-------------------|
| 6 5 12 | 179 179 127 | 48 48 3 |
| 4 9 8 | 5 6 3 | 17 17 2 |
| 7 3 12 | 148 148 128 | 6 9 5 |
*-----------------------------------------------------------* |
Looking at the outside requirements for the UR12 in r79c36, we find:
digit 1: in r34c6
digit 2: x-wing overlay
Thus a 1 must exist in r3c6 or r4c6 to prevent the deadly pattern.
This strong link can be used to form a flightless w-wing 17 with pincers on 7 in r2c4 and r4c2.
Transport the 7 pincer in r2c4: (7)r2c4 - r1c5 = r1c9 - r56c9 => in b6, either r4c7=7 or r5c8=7
(7)r4c7; r4c6<>7,
(7)r5c8 - r5c2 = r4c2; r4c6<>7 thereby deleting 7 in r4c6.
AIC: (1=9)r7c5 - (9=4)r4c5 - (4=8)r9c5 - (8=7)r1c5 - (7=1)r2c4; r7c4<>1
To complete, a finned xy-wing -178 with vertex 78 in r5c4, pincer 17 in r2c4, pincer 18 in r4c6 and fin 1 in r5c4.
If xy-wing is true, then r6c4<>1 and r3c6<>1,
If fin is true. then only r6c4<>1.
Thus r6c4<>1 to complete the puzzle.
Ted |
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Marty R.
Joined: 12 Feb 2006 Posts: 5770 Location: Rochester, NY, USA
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Posted: Thu Apr 08, 2010 5:10 am Post subject: |
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This was a fun BBDB for me. I used nine assorted steps including URs, XY, XYZ, Fin Transport, Coloring, W-Wing with pincer transport and ending on an M-Wing. |
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peterj
Joined: 26 Mar 2010 Posts: 974 Location: London, UK
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Posted: Thu Apr 08, 2010 2:32 pm Post subject: |
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Mogulmeister wrote: | This was a doozie because I went looking at chains and then decided on a different tack altogether !
Quote: | 1. UR in blocks 7 and 8 on <12> eliminating 1s in r79c6
2.A "skinny" finned swordfish on 1s in r269 eliminating 1s inR4C7 R5C8 |
Very Entertaining!! |
I assume you mean columns 269?
This one cropped up for me but I was looking at it from a multi-colouring perspective with clusters in c2, c6 and then a grouped colouring in c9 with r56c9 being my group.
I rarely ever "see" Swordfish - never mind finned ones! Good spot! |
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Mogulmeister
Joined: 03 May 2007 Posts: 1151
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Posted: Thu Apr 08, 2010 3:47 pm Post subject: |
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Thanks Peter - that is indeed what I meant!
I always look for swordfish after X-wings - same principal just one more row.
For some reason, I always get pleased when I find a jellyfish as well.
One of the other current daj puzzles (10/04/07 (A)) has a very nice jellyfish at the start. In fact when you start you can see an X-wing and there's a swordfish and a jellyfish - all on 9s! Bit like those crazy Xmas roasts where a turkey contains a duck contains a chicken.
I know its not to do with THIS puzzle but here it is anyway - eliminateds in blue. Notice the X-wing in pink and can you see the swordfish as well ?
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peterj
Joined: 26 Mar 2010 Posts: 974 Location: London, UK
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Posted: Thu Apr 08, 2010 4:53 pm Post subject: |
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Thanks. Yes can see it - though the different colours do a good job of hiding it! |
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Mogulmeister
Joined: 03 May 2007 Posts: 1151
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Posted: Thu Apr 08, 2010 5:19 pm Post subject: |
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Rolf Harris ?? |
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