Since i dont have more time for it, i have to break my subgrid tests now for a longer while. My peronal conclusion so far is, that for all known puzzles there can be found subgrids, from which an experienced solver can deduce the eliminations - normally by means of case distinctions and (relatively short) contradiction nets - needed to solve the puzzle. This way it should be possible to find a (long, but) readable solution for each puzzle.
As an example, look at this step to solve 'champagne dry' with 101 candidates:
- Code: Select all
*---------------------------------------------------------*
| 9 8 1234 | 7 346 . | 1234 . . |
| 7 . 12345 | 1234 . . | 6 . . |
| 1234 123 6 | 12348 5 . | 123478 . . |
|--------------------+--------------------+---------------|
| 1268 . 129 | 168 678 . | 278 . . |
| . . 7 | 9 348 . | 5 . . |
| . . 359 | 3468 2 . | 47 . . |
|--------------------+--------------------+---------------|
| . . 8 | 5 467 . | 9 . . |
| 2356 . 2359 | 268 1 . | 378 . . |
| 1456 . 1459 | 468 6789 3 | 178 . . |
*---------------------------------------------------------*
r9c3=9
E.g. with the 7 cases
r468c3=132,135,152,153,235(r4c7=7/8),253
the elimination can be verified manually with simple contradiction nets
My program tried to find the subgrid with the minimum number of candidates in each step. Of course some of the eliminations might not be needed. And of course much more elegant or simpler solutions might exist.
This is not the only way to get to reproducible solutions with a program, which does not know more techniques than singles. Since each known puzzle can be solved with nested single contradiction chains, you also could list them (in an optimized order). This is similar to what ravel has done (but using more than singles).
Below you can find the 23 subgrids used, until the first number in champagne dry was found. They have a maximum of 101 candidates.
When doing the same for (elev;11.1;11.1;10.8;7), i needed 23 steps with 103-118 candidates.
- Code: Select all
*-------------------------------------------------------------*
| 9 8 12345 | 7 . . | . . . |
| 7 . 12345 | 12348 . . | 6 . . |
| 1234 123 6 | 12348 . . | 123478 . . |
|--------------------+----------------+-----------------------|
| . 4 129 | 168 . 5 | 278 3 . |
| . . 7 | 9 . . | 5 . . |
| . . 359 | 3468 . . | 478 . . |
|--------------------+----------------+-----------------------|
| . . 8 | 5 . . | 9 . . |
| . . 2359 | 268 . . | 378 . . |
| . . 1459 | 468 . . | 178 2 . |
*-------------------------------------------------------------*
r2c4<>8
*------------------------------------------------------------------*
| . . 12345 | . . . | . . . |
| . . 12345 | . . . | 6 . . |
| 1234 123 6 | 12348 5 . | 123478 . . |
|-------------------+----------------------+-----------------------|
| . . 129 | 168 678 5 | 278 . . |
| . . 7 | 9 3468 . | 5 . . |
| . . 359 | 3468 2 4678 | 478 . . |
|-------------------+----------------------+-----------------------|
| . . 8 | 5 467 2467 | 9 167 367 |
| . . 2359 | 268 1 . | 378 . 4 |
| . . 1459 | 468 . 3 | 178 2 . |
*------------------------------------------------------------------*
r7c6<>6
*--------------------------------------------------------------------*
| . . 12345 | . . . | . . . |
| . . 12345 | . . . | . . . |
| 1234 123 6 | 12348 5 . | 123478 . . |
|---------------------+----------------------+-----------------------|
| . . 129 | 168 678 5 | 278 3 . |
| . . 7 | 9 3468 1468 | 5 468 268 |
| . . 359 | 3468 2 4678 | 478 . 1 |
|---------------------+----------------------+-----------------------|
| . . 8 | 5 467 247 | 9 . . |
| . . 2359 | 268 1 . | 378 . 4 |
| . . 1459 | 468 . 3 | 178 2 . |
*--------------------------------------------------------------------*
r5c5<>6
*-------------------------------------------------------------------*
| 9 8 12345 | 7 346 . | . 145 235 |
| . . . | . . . | . . . |
| . . . | . . . | . . . |
|-----------------------+---------------------+---------------------|
| . 4 129 | 168 678 5 | 278 3 . |
| . . 7 | 9 348 1468 | 5 468 268 |
| . . 359 | 3468 2 4678 | 478 . 1 |
|-----------------------+---------------------+---------------------|
| . . 8 | 5 467 247 | 9 167 367 |
| . . 2359 | 268 1 . | 378 . 4 |
| . . 1459 | 468 46789 3 | 178 2 . |
*-------------------------------------------------------------------*
r9c5<>4
*-----------------------------------------------------------------*
| . . . | 7 . . | . . . |
| . . . | . . . | . . . |
| 1234 123 6 | 12348 5 . | 123478 . . |
|--------------------+--------------------+-----------------------|
| . 4 129 | 168 . 5 | 278 3 26789 |
| 12368 1236 7 | 9 348 1468 | 5 468 268 |
| . . . | 3468 2 . | 478 . 1 |
|--------------------+--------------------+-----------------------|
| 12346 12367 8 | 5 467 247 | 9 167 367 |
| . . . | 268 . . | 378 . 4 |
| . . . | 468 . . | 178 2 . |
*-----------------------------------------------------------------*
r7c2<>7
*----------------------------------------------------------------*
| 9 8 12345 | 7 . . | . . . |
| 7 . 12345 | . . . | 6 . . |
| 1234 123 6 | 12348 . . | 123478 . . |
|---------------------+------------------+-----------------------|
| 1268 4 129 | 168 678 5 | 278 3 26789 |
| . . 7 | 9 . . | 5 . 268 |
| . . 359 | 3468 . . | 478 . 1 |
|---------------------+------------------+-----------------------|
| . . 8 | 5 467 247 | 9 167 367 |
| . . 2359 | 268 . . | 378 . . |
| . . 1459 | 468 . . | 178 . . |
*----------------------------------------------------------------*
r6c7<>8
*-------------------------------------------------------------------*
| . . 12345 | . . . | . . . |
| . . 12345 | . . . | . . . |
| 1234 123 6 | 12348 5 . | 123478 . . |
|---------------------+---------------------+-----------------------|
| . 4 129 | 168 678 5 | 278 3 . |
| . . 7 | . . . | . . . |
| 3568 3569 359 | 3468 2 4678 | 47 46789 1 |
|---------------------+---------------------+-----------------------|
| . . 8 | 5 467 247 | 9 167 . |
| . . 2359 | 268 1 . | 378 . 4 |
| . . 1459 | 468 . 3 | 178 2 . |
*-------------------------------------------------------------------*
r6c8<>4
*----------------------------------------------------------------*
| 9 8 . | 7 . . | . . . |
| 7 . . | . . . | 6 . . |
| 1234 123 6 | 12348 . . | 123478 . . |
|-----------------------+---------------------+------------------|
| 1268 4 129 | 168 . . | 278 . . |
| 12368 1236 7 | 9 . . | 5 . . |
| 3568 . 359 | 3468 . . | 47 . . |
|-----------------------+---------------------+------------------|
| 12346 1236 8 | 5 . . | 9 . . |
| 2356 235679 2359 | 268 1 . | 378 . 4 |
| 1456 . 1459 | 468 . 3 | 178 . . |
*----------------------------------------------------------------*
r8c2<>2
*----------------------------------------------------------------*
| . 8 . | 7 346 1246 | 1234 . . |
| . . . | . 3489 12489 | 6 . . |
| 1234 123 6 | 12348 5 12489 | 123478 . . |
|------------------+---------------------+-----------------------|
| . 4 . | . . . | 278 3 . |
| 12368 1236 7 | 9 348 1468 | 5 468 268 |
| . . . | . . . | 47 . . |
|------------------+---------------------+-----------------------|
| 12346 1236 8 | 5 467 247 | 9 167 367 |
| . . . | . . . | 378 . . |
| . . . | . . . | 178 2 . |
*----------------------------------------------------------------*
r3c6<>4
*------------------------------------------------------------*
| 9 8 . | 7 346 . | . . . |
| 7 . . | 1234 . . | 6 . . |
| 1234 123 6 | 12348 5 . | 123478 . . |
|----------------------+---------------------+---------------|
| 1268 4 129 | 168 678 5 | 278 . . |
| 12368 . 7 | 9 . . | 5 . . |
| 3568 . 359 | 3468 2 . | 47 . . |
|----------------------+---------------------+---------------|
| 12346 1236 8 | 5 . . | 9 . . |
| 2356 35679 2359 | 268 . . | 378 . . |
| 1456 . 1459 | 468 . . | 178 . . |
*------------------------------------------------------------*
r8c2<>5
*--------------------------------------------------------------------*
| 9 8 12345 | . . . | . . . |
| 7 . 12345 | . . . | 6 . . |
| 1234 123 6 | 12348 5 . | 123478 . . |
|----------------------+---------------------+-----------------------|
| 1268 4 129 | 168 678 5 | 278 . . |
| . . 7 | 9 . 1468 | 5 . . |
| 3568 3569 359 | 3468 2 4678 | 47 . . |
|----------------------+---------------------+-----------------------|
| . . 8 | 5 467 . | 9 . . |
| 2356 . 2359 | 268 1 . | 378 . . |
| 1456 . 1459 | 468 . 3 | 178 . . |
*--------------------------------------------------------------------*
r6c6<>4
*----------------------------------------------------------------*
| 9 8 . | 7 . . | . . . |
| 7 . . | . . . | 6 . . |
| 1234 123 6 | 12348 . . | 123478 . . |
|----------------------+--------------------+--------------------|
| . . . | 168 678 5 | 278 . . |
| 12368 1236 7 | 9 348 1468 | 5 468 268 |
| . . . | 3468 2 678 | 47 . . |
|----------------------+--------------------+--------------------|
| 12346 1236 8 | 5 467 247 | 9 . 367 |
| . . . | 268 . . | 378 . . |
| 1456 15679 . | 468 . 3 | 178 2 5678 |
*----------------------------------------------------------------*
r9c2<>1
*----------------------------------------------------------*
| 9 8 12345 | 7 346 . | 1234 . . |
| 7 . 12345 | . . . | 6 . . |
| 1234 123 6 | 12348 5 . | 123478 . . |
|---------------------+--------------------+---------------|
| . . 129 | 168 678 5 | 278 . . |
| . . 7 | 9 348 . | 5 . . |
| . . 359 | 3468 2 . | 47 . . |
|---------------------+--------------------+---------------|
| . . 8 | 5 467 . | 9 . . |
| 2356 3679 2359 | 268 1 . | 378 . . |
| . 5679 1459 | 468 6789 . | 178 . . |
*----------------------------------------------------------*
r9c3<>9
*-----------------------------------------------------------------*
| 9 8 . | 7 . . | . . . |
| 7 . . | . . . | 6 . . |
| 1234 123 6 | 12348 . . | 123478 . . |
|---------------------+--------------------+----------------------|
| . 4 129 | 168 . 5 | 278 3 26789 |
| 12368 1236 7 | 9 348 1468 | 5 468 268 |
| . . . | 3468 . . | 47 . . |
|---------------------+--------------------+----------------------|
| 12346 1236 8 | 5 467 247 | 9 167 367 |
| . . . | 268 1 26789 | 378 . 4 |
| . . . | 468 . . | 178 . . |
*-----------------------------------------------------------------*
r8c6<>2
*-------------------------------------------------------------*
| 9 8 . | 7 346 . | . . . |
| 7 1235 . | . . . | 6 . . |
| 1234 123 . | 12348 5 . | 123478 . . |
|-------------------+--------------------+--------------------|
| . 4 . | 168 678 . | 278 . . |
| 12368 1236 7 | 9 348 1468 | 5 468 268 |
| . . . | 3468 2 . | 47 . . |
|-------------------+--------------------+--------------------|
| 12346 1236 . | 5 . . | 9 . . |
| 2356 . . | 268 1 . | 378 . . |
| 1456 5679 145 | 468 . 3 | 178 2 . |
*-------------------------------------------------------------*
r9c2<>5
*--------------------------------------------------------------*
| 9 8 . | 7 346 . | . . . |
| 7 . . | . 3489 . | 6 . . |
| 1234 123 6 | 12348 5 . | 123478 . . |
|---------------------+--------------------+-------------------|
| . 4 . | 168 678 . | 278 . . |
| 12368 1236 7 | 9 348 1468 | 5 468 268 |
| . . . | . 2 . | 47 . . |
|---------------------+--------------------+-------------------|
| 12346 1236 8 | 5 467 247 | 9 167 367 |
| . . . | 268 1 . | 378 . . |
| . 679 . | 468 6789 . | 178 . . |
*--------------------------------------------------------------*
r5c5<>8
*----------------------------------------------------------------*
| 9 8 . | 7 346 1246 | . 145 235 |
| 7 1235 12345 | . 3489 12489 | 6 14589 23589 |
| 1234 123 6 | . . . | . . . |
|---------------------+--------------------+---------------------|
| . 4 . | . 678 5 | 278 3 . |
| 12368 1236 7 | 9 34 1468 | 5 468 268 |
| . . . | . . . | . . 1 |
|---------------------+--------------------+---------------------|
| 12346 1236 8 | 5 467 247 | 9 167 367 |
| . . . | . . . | . . 4 |
| . . . | . . . | . . . |
*----------------------------------------------------------------*
r2c9<>5
*-----------------------------------------------------------------*
| 9 . 12345 | 7 346 . | . . . |
| 7 . 12345 | . 3489 . | 6 . . |
| 1234 123 6 | 12348 5 . | 123478 . . |
|--------------------+--------------------+-----------------------|
| 1268 4 129 | 168 678 5 | 278 3 26789 |
| . . 7 | 9 34 . | 5 . . |
| . . 359 | 3468 2 . | 47 . . |
|--------------------+--------------------+-----------------------|
| . . 8 | 5 467 . | 9 . . |
| 2356 . 2359 | 268 1 . | 378 . . |
| 1456 . 145 | 468 . . | 178 . . |
*-----------------------------------------------------------------*
r2c5<>4
*--------------------------------------------------------------*
| 9 8 . | 7 346 1246 | 1234 . . |
| 7 . . | . 389 12489 | 6 . . |
| 1234 123 6 | 12348 5 1289 | 123478 . . |
|---------------------+--------------------+-------------------|
| . . . | . 678 5 | 278 . . |
| 12368 1236 7 | 9 34 1468 | 5 468 268 |
| . . . | . 2 . | 47 . . |
|---------------------+--------------------+-------------------|
| 12346 1236 8 | 5 467 247 | 9 167 367 |
| . . . | . . 6789 | 378 . . |
| . . . | . . 3 | 178 . . |
*--------------------------------------------------------------*
r3c6<>1
*------------------------------------------------------------------*
| . . . | 7 346 1246 | 1234 . . |
| . . . | . 389 12489 | 6 . . |
| 1234 123 6 | 12348 5 289 | 123478 . . |
|--------------------+---------------------+-----------------------|
| . . . | . 678 . | 278 . . |
| 12368 1236 7 | 9 34 1468 | 5 468 268 |
| . . . | . 2 . | 47 . . |
|--------------------+---------------------+-----------------------|
| 12346 1236 8 | 5 467 247 | 9 167 367 |
| . . . | . 1 . | 378 . . |
| . . . | . 6789 . | 178 . . |
*------------------------------------------------------------------*
r3c6<>2
*---------------------------------------------------------------*
| 9 8 . | . 346 1246 | . 145 235 |
| 7 1235 12345 | . 389 12489 | 6 14589 . |
| 1234 123 6 | . 5 89 | . . . |
|---------------------+-----------------+-----------------------|
| . . . | . 678 5 | 278 3 . |
| 12368 1236 7 | 9 34 1468 | 5 468 268 |
| . . . | . 2 . | . . 1 |
|---------------------+-----------------+-----------------------|
| 12346 1236 8 | 5 467 247 | 9 167 367 |
| . . . | . 1 . | . . . |
| . . . | . 6789 3 | . . . |
*---------------------------------------------------------------*
r2c8<>5,
*---------------------------------------------------------------*
| 9 8 1234 | 7 346 1246 | 1234 . . |
| 7 1235 12345 | 1234 . . | 6 . . |
| 1234 123 6 | 12348 . . | 123478 . . |
|---------------------+--------------------+--------------------|
| . 4 129 | 168 . . | 278 . . |
| . 1236 7 | 9 . . | 5 . . |
| . . 359 | 3468 . . | 47 . . |
|---------------------+--------------------+--------------------|
| . . 8 | 5 . . | 9 . . |
| . 3679 2359 | 268 . . | 378 . . |
| . 679 145 | 468 . 3 | 178 2 . |
*---------------------------------------------------------------*
r2c2<>1
*-----------------------------------------------------------------*
| . . 1234 | 7 . . | . . . |
| . . 12345 | . . . | . . . |
| 1234 123 6 | 12348 5 89 | 123478 . 23789 |
|---------------------+-------------------+-----------------------|
| . . 129 | 168 . 5 | 278 3 26789 |
| . . 7 | 9 . 1468 | 5 . 268 |
| . . 359 | 3468 2 678 | 47 . 1 |
|---------------------+-------------------+-----------------------|
| . . 8 | 5 467 247 | 9 167 367 |
| . . 2359 | 268 . . | 378 . 4 |
| . . 145 | 468 . . | 178 2 . |
*-----------------------------------------------------------------*
r6c4<>4
first number found (r6c6=4)
*------------------------------------------------------------------*
| 9 8 1234 | 7 346 1246 | 123 145 235 |
| 7 235 12345 | 1234 389 12489 | 6 1489 2389 |
| 1234 123 6 | 12348 5 89 | 12378 14789 23789 |
|---------------------+---------------------+----------------------|
| 1268 4 129 | 168 678 5 | 278 3 26789 |
| 12368 1236 7 | 9 34 1468 | 5 68 268 |
| 3568 3569 359 | 368 2 678 | 4 6789 1 |
|---------------------+---------------------+----------------------|
| 12346 1236 8 | 5 467 247 | 9 167 367 |
| 2356 3679 2359 | 268 1 6789 | 378 5678 4 |
| 1456 679 145 | 468 6789 3 | 178 2 5678 |
*------------------------------------------------------------------*
From here on only subgrids with maximum 76 candidates were needed.