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Ajò Dimonios
Joined: 01 May 2017
Posts: 339
Location: Sassari Italy
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 Posted: Sun Aug 05, 2018 7:13 am Post subject: A.Sudoku 4/08/2018 |
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Hy everyone
How many moves after the basic strategy?
| Code: |
+-------+-------+-------+
| . . . | 4 9 3 | . . . |
| . . 9 | 1 . 2 | 6 . . |
| 7 . . | . . . | . . 4 |
+-------+-------+-------+
| . 5 . | . 3 . | . 6 . |
| . . . | 5 . 1 | . . . |
| . 3 . | . 8 . | . 2 . |
+-------+-------+-------+
| 8 . . | . . . | . . 1 |
| . . 7 | 9 . 6 | 8 . . |
| . . . | 8 4 5 | . . . |
+-------+-------+-------+
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Play this puzzle online at the Daily Sudoku site
Ciao a Tutti
Paolo |
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dongrave
Joined: 06 Mar 2014
Posts: 568
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| Posted: Sun Aug 05, 2018 5:35 pm Post subject: |
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Sorry, this one's too tough for me! Here's the grid after basics I think.
| Code: | +----------------+------------+----------------+
| 1256 1268 1256 | 4 9 3 | 257 1578 2578 |
| 345 48 9 | 1 7 2 | 6 358 358 |
| 7 12 123 | 6 5 8 | 239 139 4 |
+----------------+------------+----------------+
| 149 5 148 | 2 3 49 | 147 6 789 |
| 249 7 248 | 5 6 1 | 34 348 389 |
| 1469 3 146 | 7 8 49 | 145 2 59 |
+----------------+------------+----------------+
| 8 469 456 | 3 2 7 | 459 459 1 |
| 2345 24 7 | 9 1 6 | 8 345 235 |
| 123 129 123 | 8 4 5 | 2379 379 6 |
+----------------+------------+----------------+
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I think I counted 7 different cells that if you have the right number you can solve it in one step but unfortunately I couldn't find any way to reach a contradiction when assuming that the cell did not contain the right value without using advanced moves (even if you assume each of the wrong values one at a time). Where did you find this one? This one is brutal! |
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immpy
Joined: 06 May 2017
Posts: 571
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| Posted: Sun Aug 05, 2018 10:53 pm Post subject: |
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This is TOO TOUGH....for me, anyway. I can't budge it. I pasted it into my solver, and it came up with numerous grouped discontinuous nice loops and several Kraken Fishes (actually Finned Franken Jellyfishes), and several Almost Locked Sets, among other things more familiar. I remain stumped and look forward to more manageable puzzles. I counted 17 advanced steps that my program needed to solve. Which is why I avoided this one when you first posted it back in April.
cheers...immp |
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Ajò Dimonios
Joined: 01 May 2017
Posts: 339
Location: Sassari Italy
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| Posted: Mon Aug 06, 2018 6:59 am Post subject: |
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Hy everyone.
Dongrave wrote:
| Code: | | I think I counted 7 different cells that if you have the right number you can solve it in one step but unfortunately I couldn't find any way to reach a contradiction when assuming that the cell did not contain the right value without using advanced moves (even if you assume each of the wrong values one at a time). Where did you find this one? This one is brutal! |
It is true there are 7 Backdoors im this puzzle.
It is resolved in two moves with the technique of the slopes. It is sufficient to show that R9C2 ≠ 9. In fact R9C2 = 9 + R8C2 = 2 and R9C2 = 9 + R8C2 = 4 create, using only the basic technique, both of the contradictions and consequently make the cell R8C2 empty when R9C2 is equal to 9. For this reason R9C2 is different from 9.
Ciao a Tutti Paolo |
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dongrave
Joined: 06 Mar 2014
Posts: 568
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| Posted: Mon Aug 06, 2018 8:06 pm Post subject: |
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| Oh, of course! Very interesting! I didn't think of that! Thanks! |
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