SE 8.3 to kick off the weekend

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SE 8.3 to kick off the weekend

Postby Draco » Fri Apr 03, 2009 4:11 am

I generated this puzzle with my solver:
Code: Select all
38.....491...4...3...3.9...4.2...1.8.6..1..9.9.5...6.2...5.7...2...9...559.....37

3  8  67   | 167  256 12   | 257  4   9
1  25 9    | 678  4   28   | 2578 268 3
67 25 4    | 3    258 9    | 2578 128 16
-----------+---------------+------------
4  3  2    | 9    7   6    | 1    5   8
78 6  78   | 2    1   5    | 3    9   4
9  1  5    | 48   38  348  | 6    7   2
-----------+---------------+------------
68 4  138  | 5    238 7    | 9    128 16
2  7  1368 | 1468 9   1348 | 48   168 5
5  9  168  | 1468 268 1248 | 248  3   7

The PM's are after singles and an X-Wing (SSTS exhausted). I have a contradiction net that needs 5 steps to crack the puzzle to singles + a couple of open patterns to get you to STE.

The net exploits a backdoor (r7c5<>2)... in case that helps you find a better path. Looking for more elegant solutions (definition of that is up to you).

Cheers...

- drac

[edit: added SSTS exhausted to text - thx Don]
Last edited by Draco on Fri Apr 03, 2009 12:25 am, edited 2 times in total.
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Postby DonM » Fri Apr 03, 2009 4:17 am

Draco, have you checked whether this is beyond the SSTS positon? I ask because, if not, then I think it would be easier to present these puzzles having run them thru SS. It seems that many people are using SS as a frontend and end up doing that anyway. It gets very confusing because you will see things such as: 'xy-wing at rxcx' at the start of solutions which is still very much SS.
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Postby ttt » Fri Apr 03, 2009 8:05 am

Code: Select all
 *-----------------------------------------------------------*
 | 3     8     67    | 167   256   12    | 257   4     9     |
 | 1     25    9     | 678   4     28    | 2578  268   3     |
 | 67    25    4     | 3     258   9     | 2578  128   16    |
 |-------------------+-------------------+-------------------|
 | 4     3     2     | 9     7     6     | 1     5     8     |
 | 78    6     78    | 2     1     5     | 3     9     4     |
 | 9     1     5     | 48    38    348   | 6     7     2     |
 |-------------------+-------------------+-------------------|
 | 68    4     138   | 5     238   7     | 9     128   16    |
 | 2     7     1368  | 1468  9     1348  | 48    168   5     |
 | 5     9     168   | 1468  268   1248  | 248   3     7     |
 *-----------------------------------------------------------*

On using Eureka!/AIC notation.
01: (hp38=2)r67c5-(2)r9c56=(2)r9c7-(2)r1c7=(2)r1c56-(2=8)r2c6 => r3c5<>8
02: (hp25=6)r13c5-(6)r2c4=(6-2)r2c8=(2)r7c8 => r7c5<>2, singles to the end
Note: hp – hidden pair

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Postby DonM » Fri Apr 03, 2009 9:14 am

ttt wrote:On using Eureka!/AIC notation.
01: (hp38=2)r67c5-(2)r9c56=(2)r9c7-(2)r1c7=(2)r1c56-(2=8)r2c6 => r3c5<>8
02: (hp25=6)r13c5-(6)r2c4=(6-2)r2c8=(2)r7c8 => r7c5<>2, singles to the end
Note: hp – hidden pair

ttt


Well, guess we'll just have to find something else to kick off this weekend!:D
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Postby Luke » Fri Apr 03, 2009 9:50 am

ttt wrote:
Code: Select all
 *-----------------------------------------------------------*
 | 3     8     67    | 167   256   12    | 257   4     9     |
 | 1     25    9     | 678   4     28    | 2578  268   3     |
 | 67    25    4     | 3     258   9     | 2578  128   16    |
 |-------------------+-------------------+-------------------|
 | 4     3     2     | 9     7     6     | 1     5     8     |
 | 78    6     78    | 2     1     5     | 3     9     4     |
 | 9     1     5     | 48    38    348   | 6     7     2     |
 |-------------------+-------------------+-------------------|
 | 68    4     138   | 5     238   7     | 9     128   16    |
 | 2     7     1368  | 1468  9     1348  | 48    168   5     |
 | 5     9     168   | 1468  268   1248  | 248   3     7     |
 *-----------------------------------------------------------*

On using Eureka!/AIC notation.
01: (hp38=2)r67c5-(2)r9c56=(2)r9c7-(2)r1c7=(2)r1c56-(2=8)r2c6 => r3c5<>8
02: (hp25=6)r13c5-(6)r2c4=(6-2)r2c8=(2)r7c8 => r7c5<>2, singles to the end

I get lost on that last strong link in move 02.
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Postby Draco » Fri Apr 03, 2009 10:20 am

Luke451 wrote:I get lost on that last strong link in move 02.

I guess I better spend some time learning Eureka notation in the future... I can't follow it at all...:(

- drac
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Postby ttt » Fri Apr 03, 2009 12:04 pm

Luke451 wrote:I get lost on that last strong link in move 02.

I don't know what you meant, but after move 01 => pair (25)r3c25 => r3c8<>2 so we have strong link (2)r2c8=(2)r7c8.

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Postby m_b_metcalf » Fri Apr 03, 2009 12:12 pm

DonM wrote:Well, guess we'll just have to find something else to kick off this weekend!:D

Here's another 8.3 (with an easy start), a by-product of the current Patterns Game.
Code: Select all
 1 . . . 2 . . . 3
 . . 4 3 . 5 6 . .
 . 7 . . . . . 4 .
 8 . . . . . . . 2
 . 2 . 9 . 6 . 1 .
 . . . . . . . . .
 . . 7 . 1 . 9 . .
 . 6 . . . . . 5 .
 . . . . 3 . . . . 

Regards,

Mike Metcalf
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Postby ttt » Fri Apr 03, 2009 12:26 pm

m_b_metcalf wrote:
DonM wrote:Well, guess we'll just have to find something else to kick off this weekend!:D

Here's another 8.3 (with an easy start), a by-product of the current Patterns Game.
Code: Select all
 1 . . . 2 . . . 3
 . . 4 3 . 5 6 . .
 . 7 . . . . . 4 .
 8 . . . . . . . 2
 . 2 . 9 . 6 . 1 .
 . . . . . . . . .
 . . 7 . 1 . 9 . .
 . 6 . . . . . 5 .
 . . . . 3 . . . . 


Sorry DonM..., and other for you:D
Code: Select all
 *-----------*
 |...|.7.|...|
 |8..|...|46.|
 |..9|..4|3..|
 |---+---+---|
 |...|.87|.3.|
 |.2.|...|.9.|
 |.6.|51.|...|
 |---+---+---|
 |..5|3..|2..|
 |.94|...|..1|
 |...|.5.|...|
 *-----------*           Au- April 03/09, tough
 *--------------------------------------------------------------------------------------*
 | 12456    1345     26       | 12689    7        1235689  | 589      1258     2589     |
 | 8        1357     27       | 129      39       12359    | 4        6        2579     |
 | 1256     157      9        | 1268     26       4        | 3        12578    2578     |
 |----------------------------+----------------------------+----------------------------|
 | 459      45       1        | 29       8        7        | 56       3        2456     |
 | 57       2        8        | 46       34       36       | 1        9        57       |
 | 479      6        3        | 5        1        29       | 78       2478     2478     |
 |----------------------------+----------------------------+----------------------------|
 | 16       178      5        | 3        49       1689     | 2        478      46789    |
 | 3        9        4        | 2678     26       268      | 5678     578      1        |
 | 126      178      267      | 146789   5        1689     | 6789     478      3        |
 *--------------------------------------------------------------------------------------*

I solved this by 02 moves (with a net/AAIC)

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Postby ronk » Fri Apr 03, 2009 2:25 pm

ttt wrote:On using Eureka!/AIC notation.
01: (hp38=2)r67c5-(2)r9c56=(2)r9c7-(2)r1c7=(2)r1c56-(2=8)r2c6 => r3c5<>8
02: (hp25=6)r13c5-(6)r2c4=(6-2)r2c8=(2)r7c8 => r7c5<>2, [color=red]

ttt, how are those hidden pairs?

Draco wrote:I guess I better spend some time learning Eureka notation in the future... I can't follow it at all...:(

Translating to NL notation:
Code: Select all
01a: r3c5 -8- als:r67c5 -2- r9c56 =2= r9c7 -2- r1c7 =2= r1c56 -2- r2c6 -8- r3c5 => r3c5<>8
01b: - r3c2 -2- r3c5 -5- r3c2 - continuous loop => r3c8<>2 (aka naked pair)
02: r7c5 -2- als:r13c5 -6- r2c4 =6= r2c8 =2= r7c8 -2- r7c5 => r7c5<>2
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Postby aran » Fri Apr 03, 2009 2:32 pm

ronk wrote:
ttt wrote:On using Eureka!/AIC notation.
01: (hp38=2)r67c5-(2)r9c56=(2)r9c7-(2)r1c7=(2)r1c56-(2=8)r2c6 => r3c5<>8
02: (hp25=6)r13c5-(6)r2c4=(6-2)r2c8=(2)r7c8 => r7c5<>2, [color=red]

ttt, how are those hidden pairs?

How are they not hidden pairs ?
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Postby ttt » Fri Apr 03, 2009 3:42 pm

ronk wrote:
ttt wrote:On using Eureka!/AIC notation.
01: (hp38=2)r67c5-(2)r9c56=(2)r9c7-(2)r1c7=(2)r1c56-(2=8)r2c6 => r3c5<>8
02: (hp25=6)r13c5-(6)r2c4=(6-2)r2c8=(2)r7c8 => r7c5<>2
ttt, how are those hidden pairs?

I don’t know…:D , I follow the name that Steve used. I’m sorry if it’s not used here.
And thank you for translating my solution to NL notation.

PS. I noted “hp – hidden pair”, because someone PM to me ask about that.

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Postby Luke » Fri Apr 03, 2009 4:41 pm

ttt wrote:
Luke451 wrote:I get lost on that last strong link in move 02.

I don't know what you meant, but after move 01 => pair (25)r3c25 => r3c8<>2 so we have strong link (2)r2c8=(2)r7c8.
ttt

Thanks, I got it. Very nice solution:) .
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Postby Draco » Fri Apr 03, 2009 7:22 pm

ronk wrote:Translating to NL notation:
Code: Select all
01a: r3c5 -8- als:r67c5 -2- r9c56 =2= r9c7 -2- r1c7 =2= r1c56 -2- r2c6 -8- r3c5 => r3c5<>8
01b: - r3c2 -2- r3c5 -5- r3c2 - continuous loop => r3c8<>2 (aka naked pair)
02: r7c5 -2- als:r13c5 -6- r2c4 =6= r2c8 =2= r7c8 -2- r7c5 => r7c5<>2

Thanks Ron -- I could follow that. ttt - very nicely done!

Cheers...

- drac
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Postby DonM » Fri Apr 03, 2009 7:27 pm

ttt wrote:
ronk wrote:
ttt wrote:On using Eureka!/AIC notation.
01: (hp38=2)r67c5-(2)r9c56=(2)r9c7-(2)r1c7=(2)r1c56-(2=8)r2c6 => r3c5<>8
02: (hp25=6)r13c5-(6)r2c4=(6-2)r2c8=(2)r7c8 => r7c5<>2
ttt, how are those hidden pairs?

I don’t know…:D , I follow the name that Steve used. I’m sorry if it’s not used here.
And thank you for translating my solution to NL notation.

PS. I noted “hp – hidden pair”, because someone PM to me ask about that.

ttt


Second go-around on this subject:

IMO, the use of the 'hp' label depends on one's conception of the pattern being used. They following were among the first, if not the first to regularly post 'hp-based' patterns in the more difficult puzzles: Steve K->David Bird->ttt->myself. Presently I see similar 'hp' use in the solutions of Aran here & a few more at Eureka. Of those, I believe only David Bird uses 'ahp'. ttt & I pretty-much use the label 'hp' the way Steve used it. So, IMO, one is on rather shakey ground, questioning the use of the label: First, someone like Steve K, the most clever manual solver I've ever seen, knew what he was doing and knew what he wanted to express and second, as long as the label reasonably allows the reader to understand/recognize the pattern, the way it is used and what is used is to a large extent discretionary.

In this particular situation, it just so happens that because of the 'internal' strong link being used, though in the reverse direction, I happen to prefer the use of 'als' because I happen to see this more as the als pattern. But that's just me. TTT prefers to use 'hp' and considering his solving skills & the fact that there's a good precedent for its use, IMO, he can use the 'hp' label in the way he prefers.
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