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Free Press March 23, 2012

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keith

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

Posted: Fri Mar 23, 2012 7:39 pm Post subject: Free Press March 23, 2012

Multi-step?

Keith

Code:

Puzzle: FP032312
+-------+-------+-------+
| . 3 . | . . . | . 6 . |
| 4 . 6 | . 3 . | 8 . 2 |
| . . 2 | 1 . . | . 5 . |
+-------+-------+-------+
| 8 . . | . . 3 | . . . |
| . . 3 | 8 . 2 | 5 . . |
| . . . | 7 . . | . . 9 |
+-------+-------+-------+
| . 9 . | . . 1 | 6 . . |
| 3 . . | . 2 . | 7 . . |
| . 1 . | . . . | . 9 . |
+-------+-------+-------+

Play this puzzle online at the Daily Sudoku site

Keith

arkietech

Joined: 31 Jul 2008
Posts: 1834
Location: Northwest Arkansas USA

Posted: Fri Mar 23, 2012 9:03 pm Post subject:

I love those "hot wings"

Code:

*-----------------------------------------------------------*
| 159 3 1589 | 2 458 458 | 49 6 7 |
| 4 5-7 6 | 59 3 579 | 8 1 2 |
|a79 8-7 2 | 1 4678 4678 | 49 5 3 |
|-------------------+-------------------+-------------------|
| 8 d4567 c579 | 56 569 3 | 1 2 46 |
|b19 46 3 | 8 19 2 | 5 7 46 |
| 156 2 15 | 7 1456 456 | 3 8 9 |
|-------------------+-------------------+-------------------|
| 2 9 578 | 4 578 1 | 6 3 58 |
| 3 568 58 | 569 2 5689 | 7 4 1 |
| 567 1 4 | 3 5678 5678 | 2 9 58 |
*-----------------------------------------------------------*
m-wing
(7=9)r3c1-r5c1=(9-7)r4c3=(7)r4c2 => r23c2<>7
stte

Edit: oops oop again Embarassed

i'm good tonight!

but not hot.
Play/print online

Last edited by arkietech on Sat Mar 24, 2012 12:05 am; edited 4 times in total

SudoQ

Joined: 02 Aug 2011
Posts: 127

Posted: Fri Mar 23, 2012 9:34 pm Post subject:

arkietech wrote:

I love those "hot wings"

Code:

*-----------------------------------------------------------*
| 159 3 1589 | 2 458 458 | 49 6 7 |
| 4 5-7 6 | 59 3 579 | 8 1 2 |
|a79 8-7 2 | 1 4678 4678 | 49 5 3 |
|-------------------+-------------------+-------------------|
| 8 d4567 c579 | 56 569 3 | 1 2 46 |
|b19 46 3 | 8 19 2 | 5 7 46 |
| 156 2 15 | 7 1456 456 | 3 8 9 |
|-------------------+-------------------+-------------------|
| 2 9 578 | 4 578 1 | 6 3 58 |
| 3 568 58 | 569 2 5689 | 7 4 1 |
| 567 1 4 | 3 5678 5678 | 2 9 58 |
*-----------------------------------------------------------*
h-wing
(7=9)r3c1-r5c1=(9-7)r3c3=(7) => r23c2<>7
stte

Your grid doesn't seem to match your string.

/SudoQ

Marty R.

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

Posted: Fri Mar 23, 2012 10:55 pm Post subject:

I wouldn't know a hot wing from a chicken wing.

Type 1 UR (46); r4c2<>46. After cleanup leaves us here:

Code:

+-------------+--------------+---------+
| 159 3 1589 | 2 458 458 | 49 6 7 |
| 4 57 6 | 59 3 579 | 8 1 2 |
| 79 78 2 | 1 4678 4678 | 49 5 3 |
+-------------+--------------+---------+
| 8 57 579 | 56 569 3 | 1 2 4 |
| 19 4 3 | 8 19 2 | 5 7 6 |
| 6 2 15 | 7 145 45 | 3 8 9 |
+-------------+--------------+---------+
| 2 9 578 | 4 578 1 | 6 3 58 |
| 3 6 58 | 59 2 589 | 7 4 1 |
| 57 1 4 | 3 5678 5678 | 2 9 58 |
+-------------+--------------+---------+

Play this puzzle online at the Daily Sudoku site

In the Type 3 UR (59) in boxes 28, either a 7 in r2c6 or 8 in r8c6 kills the DP. The 8 proves a 7 in r3c1; r2c2, r3c56<>7.

daj95376

Joined: 23 Aug 2008
Posts: 3854

Posted: Fri Mar 23, 2012 11:41 pm Post subject: Re: Free Press March 23, 2012

keith wrote:

Multi-step?

My solver used a potpourri of steps, and still ended up using an XY-Chain to finish off the puzzle. As I see it, using a single-step chain from the beginning saves a lot of headache. ( 4x M-Wing, 4x S-Wing, and 4x L2-Wing are available. )

BTW: Dan's "h-wing" is an M-Wing that goes through r4c3 (not r3c3).

Note: Every H-Wing starts and ends in the same unit ... and r3c1 & r4c2 are not in the same unit.

arkietech

Joined: 31 Jul 2008
Posts: 1834
Location: Northwest Arkansas USA

Posted: Sat Mar 24, 2012 1:26 am Post subject: Re: Free Press March 23, 2012

daj95376 wrote:

BTW: Dan's "h-wing" is an M-Wing that goes through r4c3 (not r3c3).

Note: Every H-Wing starts and ends in the same unit ... and r3c1 & r4c2 are not in the same unit.

I'm going to keep working till I understand wings Shocked

Sorry for the boo boos. Let me know if it is still wrong.

keith

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

Posted: Sat Mar 24, 2012 2:02 am Post subject:

Sudoku Susser: 1 x Simple Forcing Chains 1 x Fishy Cycles 3 x XY-Wing 2 x Unique Rectangles and Loops 4 x Intersection Removal 1 x Simple Naked Sets 18 x Pinned Squares (Not in order. The fishy cycle can be seen as a skyscraper.) Keith

tlanglet

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

Posted: Sat Mar 24, 2012 2:21 pm Post subject:

Another solution is my old friend, the "almost naked pair". anp(56=9)r4c45-r5c5=r5c1-(9=7)r3c1-(7=58)r23c2-(58=6)r8c2-r8c4=(6)r4c4; r4c2<>5, r4c29,r6c56<>6 Ted

Marty R.

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

Posted: Sat Mar 24, 2012 4:19 pm Post subject:

Marty R. wrote:

I wouldn't know a hot wing from a chicken wing.

Type 1 UR (46); r4c2<>46. After cleanup leaves us here:

Code:

Play this puzzle online at the Daily Sudoku site

In the Type 3 UR (59) in boxes 28, either a 7 in r2c6 or 8 in r8c6 kills the DP. The 8 proves a 7 in r3c1; r2c2, r3c56<>7.

Please note, as you might already have, that my grid is in error, although it doesn't change my UR solution. The grid failed to consider the locked 8s in box 7 and the 59 pair in c4. Sorry.

arkietech

Joined: 31 Jul 2008
Posts: 1834
Location: Northwest Arkansas USA

Posted: Sat Mar 24, 2012 5:09 pm Post subject:

tlanglet wrote:

Another solution is my old friend, the "almost naked pair".

anp(56=9)r4c45-r5c5=r5c1-(9=7)r3c1-(7=*58)r23c2-(58=6)r8c2-r8c4=(6)r4c4; r4c2<>5*, r4c29,r6c56<>6

Ted

Code:

*-----------------------------------------------------------*
| 159 3 1589 | 2 458 458 | 49 6 7 |
| 4 e57 6 | 59 3 579 | 8 1 2 |
|d79 e78 2 | 1 4678 4678 | 49 5 3 |
|-------------------+-------------------+-------------------|
| 8 4567 579 |a56 a569 3 | 1 2 46 |
|c19 46 3 | 8 b19 2 | 5 7 46 |
| 156 2 15 | 7 1456 456 | 3 8 9 |
|-------------------+-------------------+-------------------|
| 2 9 578 | 4 578 1 | 6 3 58 |
| 3 f568 58 |g569 2 5689 | 7 4 1 |
| 567 1 4 | 3 5678 5678 | 2 9 58 |
*-----------------------------------------------------------*
anp(56=9)r4c45-r5c5=r5c1-(9=7)r3c1-(7=*58)r23c2-(58=6)r8c2-r8c4=(6)r4c4; r4c2<>5*, r4c29,r6c56<>6

if a=56 r6c56,r4c29>56
if a4c5=9 r4c4=6, r4c2<>5 r6c56,r4c29<>6 => r6c56,r4c29<>6, r4c2<>5

I like it! Got to learn how to spot them.

Play/print online

keith

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

Posted: Sat Mar 24, 2012 5:33 pm Post subject:

Marty R. wrote:

Code:

In the Type 3 UR (59) in boxes 28, either a 7 in r2c6 or 8 in r8c6 kills the DP. The 8 proves a 7 in r3c1; r2c2, r3c56<>7.

How?

Keith

JC Van Hay

Joined: 13 Jun 2010
Posts: 494
Location: Charleroi, Belgium

Posted: Sat Mar 24, 2012 6:48 pm Post subject:

Marty's Type 3 UR(59)B28 step in Eureka! notation ... Wink

Code:

+-----------------+--------------------+-----------+
| 159 3 159 | 2 458 458 | 49 6 7 |
| 4 5-7 6 | (59) 3 (795) | 8 1 2 |
| (79) 8 2 | 1 46-7 46-7 | 49 5 3 |
+-----------------+--------------------+-----------+
| 8 57 579 | 6 59 3 | 1 2 4 |
| (19) 4 3 | 8 19 2 | 5 7 6 |
| 6 2 (15) | 7 145 45 | 3 8 9 |
+-----------------+--------------------+-----------+
| 2 9 578 | 4 578 1 | 6 3 58 |
| 3 6 (58) | (59) 2 (895) | 7 4 1 |
| 57 1 4 | 3 5678 5678 | 2 9 58 |
+-----------------+--------------------+-----------+

7r2c6=[DP(59)r28c46=8r8c6]-(8=5)r8c3-(5=1)r6c3-(1=9)r5c1-(9=7)r3c1 => -7r2c2.r3c56

keith

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

Posted: Sat Mar 24, 2012 6:58 pm Post subject:

JC Van Hay wrote:

Marty's Type 3 UR(59)B28 step in Eureka! notation ... Wink

Code:

Thanks. If you go through R9C1, you conclude R3C1=9.

Keith

JC Van Hay

Joined: 13 Jun 2010
Posts: 494
Location: Charleroi, Belgium

Posted: Sat Mar 24, 2012 7:21 pm Post subject:

keith wrote:

If you go through R9C1, you conclude R3C1=9.

Ok, this means r8c3<>5 and the DP is unneeded Exclamation

Marty's step may be advantageously replaced by the XY Chain :

Code:

+----------------+----------------+-----------+
| 159 3 159 | 2 458 458 | 49 6 7 |
| 4 57 6 | 59 3 579 | 8 1 2 |
| (79) 8 2 | 1 467 467 | 49 5 3 |
+----------------+----------------+-----------+
| 8 57 579 | 6 59 3 | 1 2 4 |
| (19) 4 3 | 8 19 2 | 5 7 6 |
| 6 2 (15) | 7 145 45 | 3 8 9 |
+----------------+----------------+-----------+
| 2 9 78-5 | 4 578 1 | 6 3 58 |
| 3 6 8-5 | 59 2 589 | 7 4 1 |
| (57) 1 4 | 3 5678 5678 | 2 9 58 |
+----------------+----------------+-----------+

(5=1)r6c3-(1=9)r5c1-(9=7)r3c1-(7=5)r9c1 => -5r78c3; stte

Marty R.

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

Posted: Sat Mar 24, 2012 9:02 pm Post subject:

Quote:

How?

Code:

+-------------+-----------------+---------+
| 159 3 1589 | 2 458 458 | 49 6 7 |
| 4 57 6 | 59 3 579 | 8 1 2 |
| E79 78 2 | 1 4678 4678 | 49 5 3 |
+-------------+-----------------+---------+
| 8 57 579 | 56 569 3 | 1 2 4 |
| D19 4 3 | 8 19 2 | 5 7 6 |
| 6 2 C15 | 7 145 45 | 3 8 9 |
+-------------+-----------------+---------+
| 2 9 578 | 4 578 1 | 6 3 58 |
| 3 6 B58 | 59 2 A589 | 7 4 1 |
| 57 1 4 | 3 5678 5678 | 2 9 58 |
+-------------+-----------------+---------+

By the way, if I may ask a question that has theoretical, but no practical, value: when doing something like this can r28c6 be considered a 78 pseudo cell?

keith

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

Posted: Sun Mar 25, 2012 12:32 am Post subject:

Marty R. wrote:

Quote:

How?

Code:

+-------------+-----------------+---------+
| 159 3 1589 | 2 458 458 | 49 6 7 |
| 4 *57 6 | 59 3 579 | 8 1 2 |
| E79 78 2 | 1 4678 4678 | 49 5 3 |
+-------------+-----------------+---------+
| 8 57 579 | 56 569 3 | 1 2 4 |
| D19 4 3 | 8 19 2 | 5 7 6 |
| 6 2 C15 | 7 145 45 | 3 8 9 |
+-------------+-----------------+---------+
| 2 9 578 | 4 578 1 | 6 3 58 |
| 3 6 *B58 | 59 2 A589 | 7 4 1 |
| 57 1 4 | 3 5678 5678 | 2 9 58 |
+-------------+-----------------+---------+

By the way, if I may ask a question that has theoretical, but no practical, value: when doing something like this can r28c6 be considered a 78 pseudo cell?

Yes, and it's not theoretical. the cells * are an XY-wing with the pseudocell, pincers on 5.

Keith

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