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Help with this puzzle http://www.rcbroughton.co.uk/sudoku/forum/viewtopic.php?f=5&t=546 |
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Author: | enxio27 [ Wed Jun 17, 2009 8:26 pm ] |
Post subject: | Help with this puzzle |
This puzzle is advertised to need nothing more difficult than a swordfish (which I've already found), but I can't get further than this, and JSudoku says it can't be solved without enabling more advanced techniques (it suggested a jellyfish). Am I missing something, or was it incorrectly advertised? Code: 26.9.7.43
73.....89 ......... 1..3.6..5 ....7.... 4..5.2..1 ......... 34.....97 92.4.3.16 +-------------------------+-------------------------+-------------------------+ | 2 6 158 | 9 158 7 | 15 4 3 | | 7 3 145 | 126 12456 145 | 156 8 9 | | 58 1589 1489 | 168 3 148 | 167 567 2 | +-------------------------+-------------------------+-------------------------+ | 1 789 289 | 3 489 6 | 24789 27 5 | | 568 589 23689 | 18 7 1489 | 234689 236 48 | | 4 789 3689 | 5 89 2 | 36789 367 1 | +-------------------------+-------------------------+-------------------------+ | 568 158 168 | 7 12689 189 | 2348 235 48 | | 3 4 1568 | 1268 12568 158 | 258 9 7 | | 9 2 7 | 4 58 3 | 58 1 6 | +-------------------------+-------------------------+-------------------------+ |
Author: | tarek [ Wed Jun 17, 2009 9:12 pm ] |
Post subject: | Re: Help with this puzzle |
It does require a Jellyfish after exhausting a regular heirarchy of solving techniques Code: *--------------------------------------------------------------------------* | 2 6 158 | 9 158 7 | 15 4 3 | | 7 3 145 | 126 12456 145 | 156 8 9 | |*58 15-89 14-89 |*168 3 *148 | 167 567 2 | |------------------------+------------------------+------------------------| | 1 789 289 | 3 489 6 | 24789 27 5 | |*568 5-89 236-89 |*18 7 *1489 | 2346-89 236 *48 | | 4 789 3689 | 5 89 2 | 36789 367 1 | |------------------------+------------------------+------------------------| |*568 15-8 16-8 | 7 126-89 *189 | 234-8 235 *48 | | 3 4 156-8 |*1268 1256-8 *158 | 25-8 9 7 | | 9 2 7 | 4 58 3 | 58 1 6 | *--------------------------------------------------------------------------* Eliminating 8 From r357c2,r3578c3,r578c7,r78c5 (3x3x4x2 Jellyfish in Columns 1469) Therefore it was not correctly advertised. tarek |
Author: | enxio27 [ Wed Jun 17, 2009 9:34 pm ] |
Post subject: | Re: Help with this puzzle |
ARRRRGGGGHHHH!!!! No wonder I was having trouble with it! I haven't gotten to jellyfish yet. This puzzle is one of a set of 5 from (I think) the Sudocue site that is supposed to help train a person to identify swordfish. I finished the other four, but this one had me stumped. Now I know why. Thanks, tarek! |
Author: | tarek [ Thu Jun 18, 2009 9:50 am ] |
Post subject: | Re: Help with this puzzle |
The Pure Swordfish thread http://www.sudoku.com/boards/viewtopic.php?t=5775 at the Players' forum has many puzzles suitable for target practice. tarek |
Author: | enxio27 [ Thu Jun 18, 2009 6:38 pm ] |
Post subject: | Re: Help with this puzzle |
tarek wrote: The Pure Swordfish thread http://www.sudoku.com/boards/viewtopic.php?t=5775 at the Players' forum has many puzzles suitable for target practice. Thanks, tarek! I'll take a look. I think I have a pretty good handle on swordfish now, but it's very rare that I find one that actually eliminates any candidates. |
Author: | Steve [ Tue Jul 07, 2009 3:38 pm ] |
Post subject: | Re: Help with this puzzle |
There is a swordfish which does the trick: Code: +-------------------+---------------------+------------------+ | 2 6 158 | 9 158 7 | 15 4 3 | | 7 3 145 | 126 12456 145 | 156 8 9 | | 58 1589 1489 | 168 3 148 | 167 567 2 | +--------------------+---------------------+-----------------+ | 1 *789 *289 | 3 *489 6 | *24789 27 5 | | 568 589 23689 | 18 7 1489 | 234689 236 48| | 4 *789 *3689 | 5 *89 2 | *36789 367 1 | +-------------------+----------------------+-----------------+ | 568 158 168 | 7 12689 189 | 2348 235 48| | 3 4 1568 | 1268 12568 158 | 258 9 7 | | 9 2 7 | 4 *58 3 | *58 1 6 | +--------------------+---------------------+-----------------+ The cells open to 8 in rows 4, 6 and 9 must contain three 8s. These cells also fall into three other houses: box 4 and columns 5 and 7. So one 8 must go in each and no other cell in any of those three houses can contain an 8. These eliminations (8 from r1c5, r5c123, r5c7, r7c57 and r8c5) reduce the puzzle to singles. Steve |
Author: | tarek [ Tue Jul 07, 2009 9:34 pm ] |
Post subject: | Re: Help with this puzzle |
congratulations steve for finding a fine fish .... In absolute terms it is indeed a swordfish, however ..... Most published puzzles have been using the swordfish to incorporate only BASIC swordfish wich means 3 rows x 3 columns or 3 columns x 3 rows (NO BOXES) What you have described is somthing called FRANKEN swordfish where boxes can be included in the 3 house x 3 house formation (NO mixing of rows and columns is allowed), IMO, this should have been explicitly mentioned beforehand. This shouldn't prevent us from admiring your fine catch.... When anything goes (mixing of rows, columns or boxes in any order in the 3x3 formation) then this is termed MUTANT swordfish ..... Here is are 2 examples with the same outcome from the above puzzle with 9 eliminations (The 2nd is actually Steve's catch ... Are you missing an elimination Steve ?). Code: 8 forms a mutant swordfish r9c9b5/r5c5b9 [r178c5][r5c1237][r78c7]<>8 8 forms a franken swordfish r4r6r9/c5c7b4 [r178c5][r5c1237][r78c7]<>8 (This is Steve's fine catch) tarek |
Author: | Steve [ Wed Jul 08, 2009 1:42 am ] |
Post subject: | Re: Help with this puzzle |
Yes, well spotted. I missed the elimination of 8 from r8c7. Thanks, tarek. Steve |
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