The New Sudoku Players' Forum

[zxc]

I am confused after reading about and implementing incompatible candidates in my solver.

The puzzle is from Andrew Stuart's Weekly Unsolvables #429 (from David Filmer)

The board position is after many moves in my solver in case your solver doesn't arrive at this position.

980700600750000090006000000640000000009600050000003000007900083005800960000020001

Code: Select all

      9       8       1234         7       1345    1245         6       124 t   24
      7       5       1234         24 t    6       124          1234    9       8
      124 b   12 b    6            1234    8       9            1237    12347   5


      6       4       128          125     157     12578        1238    123     9     12
      1238    123     9            6       14      1248         1248    5       7
      5       7       128          124     9       3            1248    124     6     124


      124     6       7            9       145     145          245     8       3
      1234    123     5            8       1347    147          9       6       24
      348     9       48           345     2       6            457     47      1     4

                      CLb          CL1                                  CL2



(124)JE2:r3c12,r2c4,r1c8

I think this is a valid JE2 exocet with incompatible base candidates 12 in r3c12.

I further think that based on "04 Incompatible Base Pair Examples v2.odt", section 3 "Example 1 - JE2", since 12 are incompatible, I can solve r3c1 as a 4.

This is not the case since 4 is not the solution to r3c1 (it is a 2).

So, somewhere, my understanding of JEs and/or incompatible pairs is wrong.

Would someone be willing to point out my mistake(s)?

Thank you,

Tim

[rjamil]

Hi Tim,

Am not expert, but, by copying your given pm state in to YZF_Sudoku and hitting "Tools -> Find all steps", gives following JE move:

Code: Select all

,-----------------,-------------------,-----------------,
| 9     8    1234 | 7     1345  1245  | 6     124    24 |
| 7     5    1234 | 24    6     124   | 1234  9      8  |
| 124   12   6    | 1234  8     9     | 1237  12347  5  |
:-----------------+-------------------+-----------------:
| 6     4    128  | 125   157   12578 | 1238  123    9  |
| 1238  123  9    | 6     14    1248  | 1248  5      7  |
| 5     7    128  | 124   9     3     | 1248  124    6  |
:-----------------+-------------------+-----------------:
| 124   6    7    | 9     145   145   | 245   8      3  |
| 1234  123  5    | 8     1347  147   | 9     6      24 |
| 348   9    48   | 345   2     6     | 457   47     1  |
'-----------------'-------------------'-----------------'

Junior Exocet:Base Cells-r3c1,r3c2;Target Cells-r1c4,r2c4,r1c8,r2c8;Cross Cells-r456789c348
JE Version POM Test:r5c56<>1

R. Jamil

[zxc]

Hello R. Jamil,

Thank you for your reply.

I will investigate the JE Version POM Test.

However, I am trying to understand why the solution to r3c1 is not a 4.

Thanks,

Tim