The New Sudoku Players' Forum

[ArkieTech]

Code: Select all

 *-----------*
 |.1.|8.2|.3.|
 |9.7|4.1|2.6|
 |...|567|...|
 |---+---+---|
 |8..|2.6|..1|
 |...|.8.|...|
 |5..|7.4|..3|
 |---+---+---|
 |...|378|...|
 |3.2|1.5|6.7|
 |.4.|6.9|.1.|
 *-----------*


Play/Print this puzzle online

[SpAce]

Code: Select all

.----------------------.---------.----------------------.
|  46      1     456   | 8  9  2 |   7     3     a[45]  |
|  9       58    7     | 4  3  1 |   2     58      6    |
|  24      238  b348   | 5  6  7 |   1     489     489  |
:----------------------+---------+----------------------:
|  8       379  b349   | 2  5  6 |   49    479     1    |
| c12(4)6  267  c1(4)6 | 9  8  3 | c(45)   24567   2-45 |
|  5       269   69    | 7  1  4 |   8     269     3    |
:----------------------+---------+----------------------:
|  16      569   1569  | 3  7  8 |   49-5  2459    2459 |
|  3       89    2     | 1  4  5 |   6     89      7    |
|  7       4    b58    | 6  2  9 |   3     1     a[5]8  |
'----------------------'---------'----------------------'

(45)r19c9 = (583-4)r934c3 = (45)r5c137 => -45 r5c9, -5 r7c7; stte

[SteveG48]

Code: Select all

 *--------------------------------------------------------------------*
 | 46     1      456    | 8      9      2      | 7      3      45     |
 | 9      58     7      | 4      3      1      | 2     b58     6      |
 |c24    c238    348    | 5      6      7      | 1     c489    489    |
 *----------------------+----------------------+----------------------|
 | 8     d379    349    | 2      5      6      |e49    d479    1      |
 | 1246   267    146    | 9      8      3      | 45     24567  245    |
 | 5      269    69     | 7      1      4      | 8      269    3      |
 *----------------------+----------------------+----------------------|
 | 16     56-9   156-9  | 3      7      8      |f459    2459   2459   |
 | 3    ab89     2      | 1      4      5      | 6     b8-9    7      |
 | 7      4      58     | 6      2      9      | 3      1      58     |
 *--------------------------------------------------------------------*


9r8c2 = 8r8c2&(89)r28c8 - (8|9=234)r3c128 - (3|4=79)r4c28 - 9r4c7 = 9r7c7 => -9r7c23,r8c8 ; stte

[SteveG48]

SpAce, that is one devilishly clever solution. So tell us how you even determined that those eliminations, two of which are needed, would give you the singles finish.

[SpAce]

SpAce, that is one devilishly clever solution. So tell us how you even determined that those eliminations, two of which are needed, would give you the singles finish.

Thanks, Steve! I found the eliminations via my normal coloring routine. Then I just tested them together after noting they didn't do much by themselves, and somewhat surprisingly the progress indicator (that you taught me to look at!) turned white. Even more surprising was that it wasn't the -45r5c9 that did the trick but the -4r5c9 and -5r7c7 together. So, none of it was planned or even predicted -- just standard procedure.

The best surprise was that the multi-elimination could be written with a simple and pretty chain. It got even better when I checked after posting what Hodoku would have used. Until then I'd assumed there were probably plenty of simple AIC solutions available, but Hodoku actually needed a forcing chain for a single-stepper. At that point I was even happier with the lucky solution that had presented itself

[eleven]

Very nice !

[SpAce]

Very nice !

Thanks, eleven! Much appreciated!

[SpAce]

Hi Steve,

9r8c2 = 8r8c2&(89)r28c8 - (8|9=234)r3c128 - (3|4=79)r4c28 - 9r4c7 = 9r7c7 => -9r7c23,r8c8 ; stte

I really like this solution too, but I don't see how the first link gives you (89)r28c8 (directly). Nevertheless, it can be easily fixed without any changes to the rest of the chain. For example:

(98)b7p59 = (89)r3c3,r8c8 - ...

[SteveG48]

Thanks, SpAce. You're right; I blundered.

[Cenoman]

I join others' kudos for SpAce's awsome solution.
I was just blown away yesterday. I couldn't post anything !

EDIT: of course, I meant awsome. Sorry SpAce, for confusing awful and awsome. There are gaps in my knowledge of English. Thank you SCLT, for spotting the misuse.

[SCLT]

I join others' kudos for SpAce's awful solution.

Perhaps you mean "awesome", rather than "awful"?

[SpAce]

Thanks, Cenoman and SCLT! I appreciate it!