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Puzzle 11/04/09: ~ Difficult++

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daj95376

Joined: 23 Aug 2008
Posts: 3854

Posted: Sat Apr 09, 2011 5:48 am Post subject: Puzzle 11/04/09: ~ Difficult++

Code:

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

Play this puzzle online at the Daily Sudoku site

peterj

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

Posted: Sat Apr 09, 2011 11:41 am Post subject:

Three steps

Quote:

skyscraper(3) c1, c5 ; r5c4<>3, r6c2<>3
same again ... but (3)r5c1 - (3=6)r5c7 - (6=1)r6c7 ; r6c5<>1
xy-wing(13-5) r1c1 ; r3c4<>5

Marty R.

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

Posted: Sun Apr 10, 2011 4:54 pm Post subject:

Examining the 25 DP in boxes 13 yielded some common outcomes. Then an M-Wing, Multi-Coloring and Remote Pairs reduced the grid to a BUG+1.

daj95376

Joined: 23 Aug 2008
Posts: 3854

Posted: Sun Apr 10, 2011 10:04 pm Post subject:

My solver's best single-step solution ... and it's far from "friendly".

Code:

after basics
+-----------------------------------------------------------------------+
| 13 7 125 | 4 135 8 | 9 6 235 |
| 8 4 125 | 135 6 9 | 7 23 235 |
| 9 35 6 | 35 2 7 | 4 8 1 |
|-----------------------+-----------------------+-----------------------|
| 6 359 158 | 7 4 15 | 123 235 89 |
| 13 2 158 | 13568 9 156 | 136 4 7 |
| 7 359 4 | 13568 135 2 | 136 35 89 |
|-----------------------+-----------------------+-----------------------|
| 4 8 7 | 156 15 156 | 23 9 23 |
| 5 6 9 | 2 7 3 | 8 1 4 |
| 2 1 3 | 9 8 4 | 5 7 6 |
+-----------------------------------------------------------------------+
# 56 eliminations remain

(3=1)r1c1 - r1c5 = r2c4 - (1=6)r7c4 - r7c6 = (6-5)r5c6 = (5)r5c3 - r12c3 = (5)r3c2 => r3c2<>3
|| ||
|| (5)r5c4 - (5=3)r3c4 => r3c2<>3
(1=5)r7c4 - (5=3)r3c4 => r3c2<>3
_______________________________________________________________________________________________

Essentially, <5> in r5c4 and r7c4 turn a nice chain into a network.

peterj

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

Posted: Mon Apr 11, 2011 10:34 am Post subject:

daj95376 wrote:

My solver's best single-step solution ... and it's far from "friendly".

You need more "lipstick on the pig" Very Happy

- patterns and als always make things look nicer!

Code:

xy-wing(15-3)[(3=1)r1c1-(1=5)r1c5-(5=3)r3c4]=(3)r1c5 - als(3=15)r6c5|r4c6 - (5)r46c5=r4c3 - r12c3=r3c2 ; r3c2<>3

ronk

Joined: 07 May 2006
Posts: 398

Posted: Mon Apr 11, 2011 2:09 pm Post subject:

peterj wrote:

daj95376 wrote:

My solver's best single-step solution ... and it's far from "friendly".

You need more "lipstick on the pig" Very Happy

- patterns and als always make things look nicer!

Code:

xy-wing(15-3)[(3=1)r1c1-(1=5)r1c5-(5=3)r3c4]=(3)r1c5 - als(3=15)r6c5|r4c6 - (5)r46c5=r4c3 - r12c3=r3c2 ; r3c2<>3

LOL! Does this smear the lipstick?

Code:

axy-wing(3)[r1c1|r3c4=r1c5] - als(3=15)r6c5|r4c6 - (5)r46c5=r4c3 - r12c3=r3c2 ; r3c2<>3

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