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[ArkieTech]

Code: Select all

 *-----------*
 |.1.|.2.|3..|
 |45.|...|...|
 |..6|...|..4|
 |---+---+---|
 |...|6..|1..|
 |2..|.7.|.4.|
 |...|..3|..5|
 |---+---+---|
 |7..|5..|.2.|
 |...|.4.|8..|
 |..9|..1|...|
 *-----------*


Play/Print this puzzle online

[eleven]

Code: Select all

 *-----------*
 |.1.|.2.|3..|
 |45.|...|...|
 |.y6|...|x.4|
 |---+---+---|
 |...|6..|1..|
 |2..|.7.|.4.|
 |...|..3|..5|
 |---+---+---|
 |7..|5..|.2.|
 |...|.4.|8..|
 |.z9|..1|x..|
 *-----------*

r3c7=5->r3c2=2
r9c7=5->r9c2=4
=>r9c2<>2, r9c4=2

[ArkieTech]

Code: Select all

After lcls
 *-----------------------------------------------------------------------------*
 | 89      1       78      | 4789    2       456789  | 3       56789   6789    |
 | 4       5       2378    | 13789   13689   6789    | 2679    16789   126789  |
 | 389    a23789   6       | 13789   13589   5789    |b2579    15789   4       |
 |-------------------------+-------------------------+-------------------------|
 | 3589    34789   34578   | 6       589     24      | 1       3789    23789   |
 | 2       3689    1358    | 189     7       589     | 69      4       3689    |
 | 1689    46789   1478    | 24      189     3       | 2679    6789    5       |
 |-------------------------+-------------------------+-------------------------|
 | 7       3468    1348    | 5       3689    689     | 469     2       1369    |
 | 1356    236     1235    | 2379    4       2679    | 8       135679  13679   |
 | 3568   d3468-2  9       | 2378    368     1       |c4567    3567    367     |
 *-----------------------------------------------------------------------------*
L-wing
2r3c2=(2-5)r3c7=(5-4)r9c7=4r9c2 => -2r9c2; stte

[tlanglet]

Same deletion, different view...

4r9c2=(4-5)r9c7=(5-2)r3c7=2r3c2 => r9c2<>2

I was really surprised when the puzzle broke with the one step.

Ted

[eleven]

Different view
Als xy-wing: (2=4)r9c145789-(4=5)r23567-(5=2)r3c124568 => r9c2<>2

[daj95376]

The same L-Wing was posted by eleven, Dan, and Ted. An ALS was also posted by eleven.

Now, find a single-stepper that doesn't use an ALS or cell r9c2. _ _

___

[pjb]

One step ALS solution with different target:

(2=4)r2567c7 - 4 - (4=2)r9c145789: => r6c4 <> 2. stte

Phil

[pjb]

Avoiding ALSs:

(2=4)r4c6-4-(4=2)r6c4-2-r6c7=2=(2-5)r3c7=5=(5-4)r9c7=4=(4-2)r9c2=2=r8c3: r8c5 <> 2

Phil

[DonM]

Avoiding ALSs:

(2=4)r4c6-4-(4=2)r6c4-2-r6c7=2=(2-5)r3c7=5=(5-4)r9c7=4=(4-2)r9c2=2=r8c3: r8c5 <> 2
Phil

While I try to be accepting of some variations of Eureka AIC notation, I'm having trouble with this. It appears that you are denoting the operative digit between '=' and '-' characters depending on whether it is a strong or weak link. But that totally confuses the reader (certainly me) who is trying to see the alternating inferences.

Not to mention that at first I thought I was looking at a new form of nice loop. Perchance, is this the way your computer solver outputs a solution?

[pjb]

Dear DonM,

You guessed right - I started my solver some time back, and its current output has to be translated. I see your point, the digits I inserted are redundant. Should it be:

(2=4)r4c6 - (4=2)r6c4 - r6c7 = (2-5)r3c7 = (5-4)r9c7 = (4-2)r9c2 = r8c3: => r8c5 <> 2; ?

If you're interested, one can make it into a type 1 discontinuous nice loop with same result starting and ending at r8c5:

(2)r8c5 -(2=4)r4c6 - (4=2)r6c4 - r6c7 = (2-5)r3c7 = (5-4)r9c7 = (4-2)r9c2 = r8c3 - r8c5: loop; => r8c5 <> 2; stte

Phil

[Leren]

Dear DonM,

You guessed right - I started my solver some time back, and its current output has to be translated. I see your point, the digits I inserted are redundant. Should it be:

(2=4)r4c6 - (4=2)r6c4 - r6c7 = (2-5)r3c7 = (5-4)r9c7 = (4-2)r9c2 = r8c3: => r8c5 <> 2; ?

If you're interested, one can make it into a type 1 discontinuous nice loop with same result starting and ending at r8c5:

(2)r8c5 -(2=4)r4c6 - (4=2)r6c4 - r6c7 = (2-5)r3c7 = (5-4)r9c7 = (4-2)r9c2 = r8c3 - r8c5: loop; => r8c5 <> 2; stte

Phil

I'm completely lost: r8c5 = 4 as a given and there are 3 2's in Box 7 so -2r9c2 = r8c3 makes no sense.

Leren

[eleven]

(2=4)r4c6-4-(4=2)r6c4-2-r6c7=2=(2-5)r3c7=5=(5-4)r9c7=4=(4-2)r9c2=2=r8c3: r8c5 <> 2

It seems that in your grid the 2 in r2c7 is already eliminated (swordfish/x-chain): r6c7=2=(2-5)r3c7
Same with the 2 in r8c2, otherwise it should say (4-2)r9c2=2=r9c4.
At the end there is a typo, should be r8c6<>2.

[pjb]

Apologies, Eleven is correct on both counts, I forgot the grid I was working on had already run the swordfish on 2's, and the r8c3 was a typo: should have been r9c4. I'll have to do with a two step solution. At least the ALS solution holds up (I hope).

Thanks, Phil