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keith

Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA

Posted: Fri Jul 16, 2010 1:37 pm Post subject: Free Press Jul 16, 2010

Code:

Puzzle: FP071610
+-------+-------+-------+
| . . 5 | . . . | 6 . . |
| . 1 . | . . . | 8 3 . |
| . . 9 | . 6 . | . . 1 |
+-------+-------+-------+
| . 5 4 | 6 . . | . . . |
| . . . | 8 . 9 | . . . |
| . . . | . . 3 | 4 2 . |
+-------+-------+-------+
| 1 . . | . 5 . | 3 . . |
| . 4 2 | . 3 . | . 7 5 |
| . . 7 | . . . | 2 . . |
+-------+-------+-------+

Play this puzzle online at the Daily Sudoku site

Keith

Marty R.

Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA

Posted: Fri Jul 16, 2010 5:02 pm Post subject:

Possibly inefficient, but effective.

Quote:

W-Wing (89)
Coloring (9)
M-Wing (27)
XYZ-Wing (279)
XY-Chain, r9c4<>1

peterj

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

Posted: Fri Jul 16, 2010 6:58 pm Post subject:

Here's a one-stepper found looking for a gm-wing around the 1&4 SL in box2 ...

Quote:

A gm-wing(14) with a pseudo-cell one end and extended at the other...

(1=5)r5c8-(5=4)r3c8 - r3c6=(4-1)r1c6=r1c4 - (1)r8c4=r8c7; r5c7<>1

..or just another AIC if you prefer.

[Edit. Sorry I made 3 errors in this AIC - now fixed. Thanks, mm]

Last edited by peterj on Sat Jul 17, 2010 4:42 pm; edited 4 times in total

daj95376

Joined: 23 Aug 2008
Posts: 3854

Posted: Fri Jul 16, 2010 9:44 pm Post subject:

Code:

(27=8)r13c2 - (8=6)r6c2 - UR[(6)r5c2 = (3)r1c1)]<27>r15c12 => r1c1<>27
+-----------------------------------------------------------------------+
| 27+3 27 5 | 12379 8 1247 | 6 49 279 |
| 4 1 6 | 279 29 5 | 8 3 279 |
| 2378 27+8 9 | 237 6 247 | 57 45 1 |
|-----------------------+-----------------------+-----------------------|
| 789 5 4 | 6 12 12 | 79 89 3 |
| 27 27+6 3 | 8 4 9 | 15 15 67 |
| 89 68 1 | 5 7 3 | 4 2 689 |
|-----------------------+-----------------------+-----------------------|
| 1 9 8 | 27 5 27 | 3 6 4 |
| 6 4 2 | 19 3 8 | 19 7 5 |
| 5 3 7 | 4 19 6 | 2 189 89 |
+-----------------------------------------------------------------------+
# 53 eliminations remain

... followed by Marty's solution sans the XY-Chain.

Last edited by daj95376 on Fri Jul 16, 2010 9:54 pm; edited 1 time in total

Marty R.

Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA

Posted: Fri Jul 16, 2010 9:53 pm Post subject:

Quote:

... followed by Marty's solution sans the XY-Chain.

Which means I missed some basics. Embarassed

daj95376

Joined: 23 Aug 2008
Posts: 3854

Posted: Fri Jul 16, 2010 10:01 pm Post subject:

Marty R. wrote:

Which means I missed some basics. Embarassed

I was simply swapping one step for another, but at different places in the sequence. I did not mean to imply that you'd missed any basics.

Regards, Danny

Marty R.

Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA

Posted: Fri Jul 16, 2010 11:06 pm Post subject:

That's OK, you can imply or say directly, I don't mind. I interpreted if someone used my solution less the final step, then I had to have missed some basics if was solvable with my steps except for the last one? Am I missing something (besides basics)?

daj95376

Joined: 23 Aug 2008
Posts: 3854

Posted: Sat Jul 17, 2010 1:58 am Post subject:

Marty R. wrote:

That's OK, you can imply or say directly, I don't mind. I interpreted if someone used my solution less the final step, then I had to have missed some basics if was solvable with my steps except for the last one? Am I missing something (besides basics)? Very Happy

That's a bad assumption -- especially in this case because I was just providing an alternate step. Since our solutions (essentially) matched except for my first step and your last step, I chose to not list all of the duplicate steps. I'm sorry that decision caused you to feel that you'd missed something.

Here is my full solution -- mostly found by my solver. Originally, the first step was UR eliminations through strong links. I went to examine that region closer and noticed the implications of r6c2=<68>. That's when I came up with my replacement first step.

Code:

after basics:
+-----------------------------------------------------------------------+
| 237 27 5 | 12379 8 1247 | 6 49 279 |
| 4 1 6 | 279 29 5 | 8 3 279 |
| 2378 278 9 | 237 6 247 | 57 45 1 |
|-----------------------+-----------------------+-----------------------|
| 789 5 4 | 6 12 12 | 79 89 3 |
| 27 267 3 | 8 4 9 | 15 15 67 |
| 89 68 1 | 5 7 3 | 4 2 689 |
|-----------------------+-----------------------+-----------------------|
| 1 9 8 | 27 5 27 | 3 6 4 |
| 6 4 2 | 19 3 8 | 19 7 5 |
| 5 3 7 | 4 19 6 | 2 189 89 |
+-----------------------------------------------------------------------+
# 53 eliminations remain

(27=8)r13c2 - (8=6)r6c2 - UR[(6)r5c2 = (3)r1c1)]<27>r15c12 => r1c1<>27

<79+2> XYZ-Wing r2c4/r2c5+r7c4 <> 2 r1c4 (or XY-Wing later)

W-Wing (8=9)r4c8 - r4c7 = r8c7 - (9=8)r9c9 => r6c9,r9c8<>8 -or-
W-Wing (8=9)r4c8 - r1c8 = r12c9 - (9=8)r9c9 => r6c9,r9c8<>8

c58r9 Skyscraper <> 9 r1c4,r2c9

M-Wing Type 7B (7=2)r1c2 - r1c9 = (2-7)r2c9 = (7)r2c4 => r1c46<>7

My first step made it unnecessary for an XY-Chain after the M-Wing.

Regards, Danny

tlanglet

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

Posted: Sat Jul 17, 2010 3:35 am Post subject:

A patterned one stepper is

Quote:

ANP(27=4)r37c6-(4=5)r38-(5=7)r3c7-(7=9)r4c7-(9=1)r8c7-r8c4=r9c5-(1=2)r4c5; r4c6<>2

Ted

tlanglet

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

Posted: Sat Jul 17, 2010 3:42 am Post subject:

daj95376 wrote:

Code:

Danny, very nice use of the Type 6 UR27. I looked at it in isolation but no deletions.

Ted

keith

Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA

Posted: Sat Jul 17, 2010 8:57 am Post subject:

After basics:

Code:

+-------------------+-------------------+-------------------+
| 237 27 5 | 12379 8 1247 | 6 49 279 |
| 4 1 6 | 279 29 5 | 8 3 279 |
| 2378 278 9 | 237 6 247 | 57 45 1 |
+-------------------+-------------------+-------------------+
| 789 5 4 | 6 12 12 | 79 89 3 |
| 27 267 3 | 8 4 9 | 15 15 67 |
| 89 68 1 | 5 7 3 | 4 2 689 |
+-------------------+-------------------+-------------------+
| 1 9 8 | 27 5 27 | 3 6 4 |
| 6 4 2 | 19 3 8 | 19 7 5 |
| 5 3 7 | 4 19 6 | 2 189 89 |
+-------------------+-------------------+-------------------+

Pseudocell 59 in B3C8 makes an XY-wing 57-9. R4C8 <>9.
M-wing 2-7. R1B2 <>7.
XY-wing -279. R13C4 <>2.
SS 9 in C58. R1C4, R2C9 <> 9.
M-wing -79 with transport. R1C9<>7.
Pseudocell 89 in R6 makes an XY-wing -289. R1C12 <>2.

For what it's worth.

Keith

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