The New Sudoku Players' Forum

by **daj95376** » Sun Apr 28, 2013 12:56 am

Code: Select all: +-----------------------+ | 7 . . | . . . | . 9 3 | | . 9 . | . . 4 | 8 . . | | . . 2 | . 9 . | 7 . . | |-------+-------+-------| | . . . | 7 . . | . 4 . | | . . 3 | . . 9 | 6 . 7 | | . 7 . | . 6 2 | 9 3 . | |-------+-------+-------| | . 2 4 | . 3 6 | 5 . 9 | | 6 . . | 9 . 8 | . 2 4 | | 9 . . | . 4 . | 3 8 . | +-----------------------+

Play this puzzle online at the Daily Sudoku site

by **ArkieTech** » Sun Apr 28, 2013 2:10 am

Code: Select all: *-----------------------------------------------------------* | 7 158 1568 | 68 2 15 | 4 9 3 | | 135 9 156 | 36 7 4 | 8 15 2 | | 34 48 2 | 38 9 15 | 7 6 15 | |-------------------+-------------------+-------------------| |a15 6 9 | 7 b18 3 | 2 4 18-5 | | 2 1458 3 | 45 c18 9 | 6 d15 7 | | 145 7 158 | 45 6 2 | 9 3 158 | |-------------------+-------------------+-------------------| | 8 2 4 | 1 3 6 | 5 7 9 | | 6 3 7 | 9 5 8 | 1 2 4 | | 9 15 15 | 2 4 7 | 3 8 6 | *-----------------------------------------------------------* w-wing (5=1)r4c1-r4c5=r5c5-(1=5)r5c8 => -5r4c9 *-----------------------------------------------------------* | 7 158 1568 | 68 2 15 | 4 9 3 | | 3-1 9 156 | 36 7 4 | 8 c15 2 | | 34 48 2 | 38 9 15 | 7 6 15 | |-------------------+-------------------+-------------------| | 5 6 9 | 7 18 3 | 2 4 18 | | 2 b148 3 | 45 b18 9 | 6 b15 7 | |a14 7 18 | 45 6 2 | 9 3 158 | |-------------------+-------------------+-------------------| | 8 2 4 | 1 3 6 | 5 7 9 | | 6 3 7 | 9 5 8 | 1 2 4 | | 9 15 15 | 2 4 7 | 3 8 6 | *-----------------------------------------------------------* als XY-Wing (1=4)r6c1-(4=5)r5c258-(5=1)r2c8 => -1r2c1; ste

by **Marty R.** » Sun Apr 28, 2013 4:56 am

Code: Select all: *-----------------------------------------------------------* | 7 158 1568 | 68 2 15 | 4 9 3 | | 135 9 156 | 36 7 4 | 8 15 2 | | 34 48 2 | 38 9 15 | 7 6 15 | |-------------------+-------------------+-------------------| |a15 6 9 | 7 b18 3 | 2 4 18-5 | | 2 1458 3 | 45 c18 9 | 6 d15 7 | | 145 7 158 | 45 6 2 | 9 3 158 | |-------------------+-------------------+-------------------| | 8 2 4 | 1 3 6 | 5 7 9 | | 6 3 7 | 9 5 8 | 1 2 4 | | 9 15 15 | 2 4 7 | 3 8 6 | *-----------------------------------------------------------*

I played Dan's W-Wing, r4c9,r5c2<>5
Sashimi X-Wing (1), c18=>r5c2<>1
BUG+1=>r2c3=1

by **JC Van Hay** » Sun Apr 28, 2013 7:55 am

Code: Select all: +---------------------+--------------+----------------+ | 7 158 1568 | 68 2 15 | 4 9 3 | | 35(1) 9 156 | 36 7 4 | 8 (15) 2 | | 34 48 2 | 38 9 15 | 7 6 15 | +---------------------+--------------+----------------+ | (15) 6 9 | 7 18 3 | 2 4 18(5) | | 2 158(4) 3 | (45) 18 9 | 6 1-5 7 | | 5(14) 7 158 | 45 6 2 | 9 3 158 | +---------------------+--------------+----------------+ | 8 2 4 | 1 3 6 | 5 7 9 | | 6 3 7 | 9 5 8 | 1 2 4 | | 9 15 15 | 2 4 7 | 3 8 6 | +---------------------+--------------+----------------+

Chain[5] : (5=1)r2c8-1r2c1=*[5r4c9=(5-1)r4c1=*(1-4)r6c1=4r5c2-(4=5)r5c4] -> 5r2c8=5r4c9=5r5c4 :=> -5r5c8; ste
or
Kraken 1C1 -> 5r2c8=5r4c9=5r5c4 :=> -5r5c8; ste
1r2c1-(1=5)r2c8
||
1r4c1-5r4c1=5r4c9
||
1r6c1-4r6c1=4r5c2-(4=5)r5c4

by **Leren** » Sun Apr 28, 2013 11:24 am

Code: Select all: *--------------------------------------------------------------* | 7 158 1568 | 68 2 15 | 4 9 3 | | 135 9 156 | 36 7 4 | 8 15 2 | | 34 48 2 | 38 9 15 | 7 6 15 | |--------------------+--------------------+--------------------| |a15 6 9 | 7 a18 3 | 2 4 18-5 | | 2 148-5 3 | 45 b18 9 | 6 b15 7 | | 145 7 158 | 45 6 2 | 9 3 158 | |--------------------+--------------------+--------------------| | 8 2 4 | 1 3 6 | 5 7 9 | | 6 3 7 | 9 5 8 | 1 2 4 | | 9 15 15 | 2 4 7 | 3 8 6 | *--------------------------------------------------------------*

als-xz rule x = 8, z = 5: (5=8) r4c15 - ( 8=5) r5c58 => -5 r4c9, r5c2

Code: Select all: *--------------------------------------------------------------* | 7 158 1568 | 68 2 15 | 4 9 3 | |b13 9 156 | 36 7 4 | 8 a15 2 | | 34 48 2 | 38 9 15 | 7 6 15 | |--------------------+--------------------+--------------------| | 5 6 9 | 7 18 3 | 2 4 18 | | 2 d148 3 |e45 18 9 | 6 1-5 7 | |c14 7 18 | 45 6 2 | 9 3 158 | |--------------------+--------------------+--------------------| | 8 2 4 | 1 3 6 | 5 7 9 | | 6 3 7 | 9 5 8 | 1 2 4 | | 9 15 15 | 2 4 7 | 3 8 6 | *--------------------------------------------------------------*

(5=1) r2c9 - r2c1 = (1-4) r6c1 = r5c2 - (4=5) r5c4 => -5 r5c8; stte

Leren

by **tlanglet** » Sun Apr 28, 2013 1:12 pm

Code: Select all: *-----------------------------------------------------------* | 7 (58)1 (58)16| (8)6 2 i15 | 4 9 3 | | 135 9 156 | 36 7 4 | 8 f15 2 | | 34 b48 2 |a38 9 h15 | 7 6 g15 | |-------------------+-------------------+-------------------| | 15 6 9 | 7 18 3 | 2 4 158 | | 2 c1458 3 |d45 18 9 | 6 e15 7 | | 145 7 158 | 45 6 2 | 9 3 158 | |-------------------+-------------------+-------------------| | 8 2 4 | 1 3 6 | 5 7 9 | | 6 3 7 | 9 5 8 | 1 2 4 | | 9 15 15 | 2 4 7 | 3 8 6 | *-----------------------------------------------------------*

An Almost Naked Set with a long tail............
ANS[58r1c23=8r1c4]-r3c4=(8-4)r3c2=r5c2-(4=5)r5c4-r5c8=5*r2c8-(5=1)r3c9-r3c6=1r1c6 => r2c13<>5*, r1c23<>1

Ted

by **daj95376** » Sun Apr 28, 2013 3:34 pm

tlanglet wrote:
Code: Select all
*-----------------------------------------------------------* | 7 (58)1 (58)16| (8)6 2 i15 | 4 9 3 | | 135 9 156 | 36 7 4 | 8 f15 2 | | 34 b48 2 |a38 9 h15 | 7 6 g15 | |-------------------+-------------------+-------------------| | 15 6 9 | 7 18 3 | 2 4 158 | | 2 c1458 3 |d45 18 9 | 6 e15 7 | | 145 7 158 | 45 6 2 | 9 3 158 | |-------------------+-------------------+-------------------| | 8 2 4 | 1 3 6 | 5 7 9 | | 6 3 7 | 9 5 8 | 1 2 4 | | 9 15 15 | 2 4 7 | 3 8 6 | *-----------------------------------------------------------*

An Almost Naked Set with a long tail............
ANS[58r1c23=8r1c4]-r3c4=(8-4)r3c2=r5c2-(4=5)r5c4-r5c8=5*r2c8-(5=1)r3c9-r3c6=1r1c6 => r2c13<>5*, r1c23<>1

Hmmm! I'm having trouble with your first strong inference. I see: [7 18 18 6 2 5 4 9 3] as possible in [r1] where r1c23<>58 and r1c4<>8.

by **daj95376** » Sun Apr 28, 2013 3:51 pm

JC: Congratulations on finding a better way to use Kraken 1C1 than the cumbersome elimination that I managed to construct.

My solver found an M-Wing that (may have) resulted in simpler choices for the second step.

Code: Select all: +--------------------------------------------------------------+ | 7 158 1568 | 68 2 15 | 4 9 3 | | 135 9 156 | 36 7 4 | 8 15 2 | | 34 48 2 | 38 9 15 | 7 6 15 | |--------------------+--------------------+--------------------| | 15 6 9 | 7 18 3 | 2 4 158 | | 2 1458 3 | 45 18 9 | 6 15 7 | | 145 7 158 | 45 6 2 | 9 3 158 | |--------------------+--------------------+--------------------| | 8 2 4 | 1 3 6 | 5 7 9 | | 6 3 7 | 9 5 8 | 1 2 4 | | 9 15 15 | 2 4 7 | 3 8 6 | +--------------------------------------------------------------+ # 37 eliminations remain M-Wing 7B (1=8)r4c5 - r4c9 = (8-1)r6c9 = (1)r6c13 => r4c1<>1

Code: Select all: take your pick +--------------------------------------------------------------+ | 7 158 1568 | 68 2 15 | 4 9 3 | | 13 9 156 | 36 7 4 | 8 15 2 | | 34 48 2 | 38 9 15 | 7 6 15 | |--------------------+--------------------+--------------------| | 5 6 9 | 7 18 3 | 2 4 18 | | 2 148 3 | 45 18 9 | 6 15 7 | | 14 7 18 | 45 6 2 | 9 3 158 | |--------------------+--------------------+--------------------| | 8 2 4 | 1 3 6 | 5 7 9 | | 6 3 7 | 9 5 8 | 1 2 4 | | 9 15 15 | 2 4 7 | 3 8 6 | +--------------------------------------------------------------+ # 31 eliminations remain S-Wing (1)r6c1 = r2c1 - (1=5)r2c8 - r3c9 = (5)r6c9 => r6c9<>1 L-Wing (1)r6c1 = r2c1 - r2c8 = (1-5)r3c9 = (5)r6c9 => r6c9<>1 S-Wing (1)r6c1 = r2c1 - (1=5)r2c8 - r5c8 = (5)r6c9 => r6c9<>1 L-Wing (1)r6c1 = r2c1 - r2c8 = (1-5)r5c8 = (5)r6c9 => r6c9<>1 L-Wing (1)r5c8 = r2c8 - r2c1 = (1-4)r6c1 = (4)r5c2 => r5c2<>1

I find it (mildly) interesting how often an S-Wing and an L-Wing will use the same cells and derive the same elimination.

by **tlanglet** » Sun Apr 28, 2013 6:03 pm

daj95376 wrote:
tlanglet wrote:
Code: Select all
*-----------------------------------------------------------* | 7 (58)1 (58)16| (8)6 2 i15 | 4 9 3 | | 135 9 156 | 36 7 4 | 8 f15 2 | | 34 b48 2 |a38 9 h15 | 7 6 g15 | |-------------------+-------------------+-------------------| | 15 6 9 | 7 18 3 | 2 4 158 | | 2 c1458 3 |d45 18 9 | 6 e15 7 | | 145 7 158 | 45 6 2 | 9 3 158 | |-------------------+-------------------+-------------------| | 8 2 4 | 1 3 6 | 5 7 9 | | 6 3 7 | 9 5 8 | 1 2 4 | | 9 15 15 | 2 4 7 | 3 8 6 | *-----------------------------------------------------------*

An Almost Naked Set with a long tail............
ANS[58r1c23=8r1c4]-r3c4=(8-4)r3c2=r5c2-(4=5)r5c4-r5c8=5*r2c8-(5=1)r3c9-r3c6=1r1c6 => r2c13<>5*, r1c23<>1

Hmmm! I'm having trouble with your first strong inference. I see: [7 18 18 6 2 5 4 9 3] as possible in [r1] where r1c23<>58 and r1c4<>8.

Danny, I treated the solution as an almost HIDDEN set, but posted it as an almost NAKED set. Sorry about that......

Ted

by **daj95376** » Sun Apr 28, 2013 8:51 pm

tlanglet wrote:Danny, I treated the solution as an almost HIDDEN set, but posted it as an almost NAKED set. Sorry about that......

Ted, I understood that you were using AHS instead of ANS, but it still failed. Reading from r-to-l, if r1c4<>8, then <8> can be forced into r1c23, but <5> can't be forced into r1c23 because of the presence of <5> in r1c6.

by **tlanglet** » Sun Apr 28, 2013 10:32 pm

daj95376 wrote:
tlanglet wrote:Danny, I treated the solution as an almost HIDDEN set, but posted it as an almost NAKED set. Sorry about that......

Ted, I understood that you were using AHS instead of ANS, but it still failed. Reading from r-to-l, if r1c4<>8, then <8> can be forced into r1c23, but <5> can't be forced into r1c23 because of the presence of <5> in r1c6.

Danny, my initial strong inference is simply incorrect, and my prior response was focused on the typo ANS instead of AHS.

Sorry about the mess-up........ :oops:

Ted

The New Sudoku Players' Forum

There Was a Time: 04/28/13

There Was a Time: 04/28/13

Re: There Was a Time: 04/28/13

Re: There Was a Time: 04/28/13

Re: There Was a Time: 04/28/13

Re: There Was a Time: 04/28/13

Re: There Was a Time: 04/28/13

Re: There Was a Time: 04/28/13

Re: There Was a Time: 04/28/13

Re: There Was a Time: 04/28/13

Re: There Was a Time: 04/28/13

Re: There Was a Time: 04/28/13