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Puzzle 11/03/28: ~ Difficult++

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daj95376

Joined: 23 Aug 2008
Posts: 3854

Posted: Mon Mar 28, 2011 6:24 pm Post subject: Puzzle 11/03/28: ~ Difficult++

Code:

+-----------------------+
| . 3 . | 1 . . | . . 5 |
| 2 9 . | . . 3 | . 7 4 |
| . . 1 | . . . | . 2 3 |
|-------+-------+-------|
| 8 . . | 2 . . | 3 . . |
| . . . | . 8 . | . 1 2 |
| . 1 . | . . . | 8 . . |
|-------+-------+-------|
| . . . | 4 . 6 | 2 3 . |
| . 6 3 | . 2 . | 7 4 1 |
| 4 2 8 | . 1 . | . 6 . |
+-----------------------+

Play this puzzle online at the Daily Sudoku site

tlanglet

Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills

Posted: Tue Mar 29, 2011 12:34 am Post subject:

Many of the patterns I tried ended in the same useless paths.

Four steps:

Quote:

#1: Flightless w-wing (59)r5c6|r8c1 SL (5)r57c2 plus transport: (9)r8c1-r8c4=(9)r7c5; r4c5<>9
#2: Flightless Up-Down skyscraper (5)r5c26 with two transports; r3c4,r7c3<>5
(5)r3c6-r2c5=(5)r2c3;
(5)r7c2-r8c1=r8c4
#3: axy-wing (79-5) vertex (79)r7c3 with fin (67)r4c3; r5c2<>5
If fin (67)r5c3 is true: LS(67)r4c39-(67=5)r4c5-r7c5=(5)r7c2
#4: Coloring 5

Ted

storm_norm

Joined: 18 Oct 2007
Posts: 1741

Posted: Tue Mar 29, 2011 8:43 am Post subject:

here is a nice and sick two step solution. its my first attempt at a youtube video. enjoy! http://www.youtube.com/watch?v=Kzf2EqYpo5U

peterj

Joined: 26 Mar 2010
Posts: 974
Location: London, UK

Posted: Tue Mar 29, 2011 10:11 am Post subject:

Norm, nice video - and nice solution! I dont know how you manage to use all those different helpers - I have never advanced beyond SS.

Quote:

here is a nice and sick

Are you attempting street language or was "sick" meant to be "slick"? Smile

I visited to post pretty much the exact same solution - though using r4 in the potential x-wing.. I'll post it just for those who don't want to watch your Premier on Youtube...

Quote:

kraken x-wing(5) r2c35, r4c35 ; r7c5<>5
||
(5)r4c8 - (9)r4c8=r6c8 - r6c1=r8c1 - (9=5)r8c4
colouring(5) or w-wing(59)

storm_norm

Joined: 18 Oct 2007
Posts: 1741

Posted: Tue Mar 29, 2011 5:39 pm Post subject:

peterj wrote:

Norm, nice video - and nice solution! I dont know how you manage to use all those different helpers - I have never advanced beyond SS.

Quote:

here is a nice and sick

Are you attempting street language or was "sick" meant to be "slick"? Smile

I visited to post pretty much the exact same solution - though using r4 in the potential x-wing.. I'll post it just for those who don't want to watch your Premier on Youtube...

Quote:

kraken x-wing(5) r2c35, r4c35 ; r7c5<>5
||
(5)r4c8 - (9)r4c8=r6c8 - r6c1=r8c1 - (9=5)r8c4
colouring(5) or w-wing(59)

thankyou.
I am one of those who thinks that a major leap in insight into advanced solutions is offering images and graphics and video to help explain the "method of madness."
I have always felt that there is a void from simply reading descriptions of solutions. a video will hopefully fill in that gap in understanding.
just because I understand a solution for what it is, doesn't mean the reader of my solution will understand what I saw.
a video will hopefully let the reader see what I see and hopefully allow them to learn/understand more about the beauty of some totally far out yet awesome solutions.

it was most definitely street language.

daj95376

Joined: 23 Aug 2008
Posts: 3854

Posted: Tue Mar 29, 2011 10:45 pm Post subject:

Code:

after basics
+--------------------------------------------------------------+
| 67 3 4 | 1 679 2 | 69 8 5 |
| 2 9 56 | 8 56 3 | 1 7 4 |
| 567 8 1 | 5679 4 59 | 69 2 3 |
|--------------------+--------------------+--------------------|
| 8 4 5679 | 2 5679 1 | 3 59 67 |
| 3 57 5679 | 5679 8 59 | 4 1 2 |
| 569 1 2 | 5679 3 4 | 8 59 67 |
|--------------------+--------------------+--------------------|
| 1 57 579 | 4 59 6 | 2 3 8 |
| 59 6 3 | 59 2 8 | 7 4 1 |
| 4 2 8 | 3 1 7 | 5 6 9 |
+--------------------------------------------------------------+
# 42 eliminations remain

r2c6 2-String Kite <> 5 r5c3 extraneous
r8c2 2-String Kite <> 5 r5c4
r25c3 Skyscraper <> 6 r3c4,r4c5 extraneous
r57\c35 Sashimi X-Wing <> 9 r4c5 extraneous

Leaving this grid (w/extraneous eliminations performed):

Code:

+--------------------------------------------------------------+
| 67 3 4 | 1 679 2 | 69 8 5 |
| 2 9 56 | 8 56 3 | 1 7 4 |
| 567 8 1 | 579 4 9-5 | 69 2 3 |
|--------------------+--------------------+--------------------|
| 8 4 5679 | 2 57 1 | 3 59 67 |
| 3 57 679 | 679 8 59 | 4 1 2 |
| (569) 1 2 | 5679 3 4 | 8 59 67 |
|--------------------+--------------------+--------------------|
| 1 57 579 | 4 59 6 | 2 3 8 |
| 59 6 3 | 59 2 8 | 7 4 1 |
| 4 2 8 | 3 1 7 | 5 6 9 |
+--------------------------------------------------------------+
# 37 eliminations remain

Although my solver found a SIN akin to Peter's Kraken X-Wing, I ignored it and examined another SIN that offered more secondary eliminations. Unfortunately, the best I managed to do with it was a Kraken Cell [r6c1]:

Code:

(5)r6c1 - r5c2 = r5c6 - (5)r3c6

(6)r6c1 - (67=5)r13c1 - (5)r3c6

(9=5)r6c8 - (5)r6c4
/ \
(9)r6c1 - = (5)r3c4 - (5)r3c6
\ /
(9=5)r8c1 - (5)r8c4

The only reason I included this solution is because of the forcing network used for r6c1=9. The streams quickly force r6c4<>5 and r8c4<>5; and these eliminations immediately force r3c4=5. Simple and clean, yet (probably) not possible to describe as a (reasonable) chain.

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