The New Sudoku Players' Forum

[ArkieTech]

Code: Select all

 *-----------*
 |6..|..5|.8.|
 |2.9|...|1..|
 |...|7..|.3.|
 |---+---+---|
 |..3|..8|...|
 |...|5.9|...|
 |...|6..|7..|
 |---+---+---|
 |.6.|..3|...|
 |..1|...|8.9|
 |.5.|4..|..6|
 *-----------*


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[Leren]

Code: Select all

*--------------------------------------------------------------------------------*
| 6       1347    47       |b39      1249    5        |c249     8       247      |
| 2       3478    9        |a38     a468    a46       | 1      a456     457      |
| 1458    148     458      | 7       124689  1246     | 2469    3       24       |
|--------------------------+--------------------------+--------------------------|
| 457     2479    3        | 1       247     8        | 2456    24569   245      |
| 1478    12478   6        | 5       2347    9        |c24      124     38       |
| 1458    12489   458      | 6       234     24       | 7       12459   38       |
|--------------------------+--------------------------+--------------------------|
| 4789    6       2478     | 89      589     3        |c245     247-5   1        |
| 3       47      1        | 2       56      67       | 8       47-5    9        |
| 789     5       278      | 4       189     17       | 3       27      6        |
*--------------------------------------------------------------------------------*

als xy-wing: (5=3) r2c4568 - (3=9) r1c4 - (9=5) r157c7 => r78c8 <> 5; stte

Leren

[eleven]

To answer Don's question to aran in the other thread from my side with this example.

After some time i wanted to use an almost w-wing 56 in r2c8,r8c5, which might eliminate the 5 in r8c8 and give a number. However there is only an almost strong link for 6 in c6, because r3c6 can be 6 too, and there is a 4 in r2c8 too.
Then i found r3c6=6->r135c7=249 -> r7c7=5 (=> r8c8<>5) and
r2c8=4->r2c56=68->r2c4=3->r1c4=9->r15c7=24->r7c7=5 (=> r8c8<>5)

But this last chain can be started also as r2c8<>5->r2c68=46->r2c5=8->...->r7c7=5 => r8c8<>5, very similar to Leren's:
(5=46)r2c8-(46=389)r1c4,r2c45-(9=245)r157c7 => r8c8<>5
So i didn't need those, i originally had started with. This often happens, as well as a contradiction somewhere.

[tlanglet]

Not as elegant as Leren's but I did not have the time to look further....

ANS(9=24)r15c7-(24=5)r7c7-(5=1)r7c45,r9c5-1r1c5=(1-3)r1c2=3r1c4 => r1c4<>9

[daj95376]

Not as elegant as Leren's but I did not have the time to look further....

ANS(9=24)r15c7-(24=5)r7c7-(5=1)r7c45,r9c5-1r1c5=(1-3)r1c2=3r1c4 => r1c4<>9

Ted, looking further may not have been any better. A non-ALS solution.

Code: Select all

 +--------------------------------------------------------------------------------+
 |  6      e1347    47      | d39      1249    5       | c249     8       247     |
 |  2      f3478    9       |  38      468     46      |  1       456    g457     |
 |  1458    148     458     |  7       124689  1246    | b2469    3       24      |
 |--------------------------+--------------------------+--------------------------|
 |  457     2479    3       |  1       247     8       | a2456    24569  h245     |
 |  1478    12478   6       |  5       2347    9       |  24      124     38      |
 |  1458    12489   458     |  6       234     24      |  7       12459   38      |
 |--------------------------+--------------------------+--------------------------|
 |  4789    6       2478    |  89      589     3       |  245     2457    1       |
 |  3       47      1       |  2       56      67      |  8       457     9       |
 |  789     5       278     |  4       189     17      |  3       27      6       |
 +--------------------------------------------------------------------------------+
 # 116 eliminations remain

 (6)r4c7 = (6-9)r3c7 = r1c7 - (9=3)r1c4 - r1c2 = (3-7)r2c2 = (7-5)r2c9 = (5)r4c9  =>  r4c7<>5