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immpy
Joined: 06 May 2017 Posts: 571
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Posted: Sun Apr 05, 2020 12:16 am Post subject: Unfair 040420 |
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Hello everyone,
Enjoy the puzzle...
Code: |
+-------+-------+-------+
| 2 7 . | . . 8 | 1 . . |
| . . . | 3 7 . | 2 . . |
| . . . | . 2 . | . . 6 |
+-------+-------+-------+
| 3 1 . | . 5 . | . . 7 |
| 7 . . | 1 3 4 | . . 9 |
| 9 . . | . 8 . | . 1 2 |
+-------+-------+-------+
| 1 . . | . 6 . | . . . |
| . . 9 | . 1 3 | . . . |
| . . 3 | 9 . . | . 5 1 |
+-------+-------+-------+
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Play this puzzle online at the Daily Sudoku site
cheers...immp |
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Clement
Joined: 24 Apr 2006 Posts: 1111 Location: Dar es Salaam Tanzania
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Posted: Tue Apr 07, 2020 9:22 am Post subject: Unfair 040420 |
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Three Steps Code: |
+-------------------------+-------------------+------------------------+
| 2 7 456 | 456 9 8 | 1 34 345 |
| 456 9 1456 | 3 7 156 | 2 48 458 |
| 458 3 1458 | 45 2 15 |{79} 79 6 |
+-------------------------+-------------------+------------------------+
| 3 1 68 | 2 5 9 | 468 468 7 |
| 7 68 2 | 1 3 4 | 5 68 9 |
| 9 45 45 | 67 8 67 | 3 1 2 |
+-------------------------+-------------------+------------------------+
| 1 2458 7 | 58 6 25 |{489} 239-48 3-48 |
| 4568 24568 9 | 578 1 3 |{4678} 27-468 {48} |
| 68 268 3 | 9 4 27 |{678} 5 1 |
+-------------------------+-------------------+------------------------+
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Step 1: Sue-De-Coq AALS in Box 9 {46789}r789c7.Other Cells {48}r8c9 in the Box and {79}r3c7 along the column.
Eliminations: Candidates which can see ALL the candidates inside the pattern => - 48r7c89,468r8c8(does not solve it) Unfair
Code: |
+-------------------------+--------------------+----------------------+
| 2 7 456 |b456 9 8 | 1 3 45 |
| 456 9 1456 | 3 7 a156 | 2 48 458 |
| 458 3 1458 |b45 2 a15 | 79 79 6 |
+-------------------------+--------------------+----------------------+
| 3 1 68 | 2 5 9 | 468 468 7 |
| 7 68 2 | 1 3 4 | 5 68 9 |
| 9 45 45 | 67 8 67 | 3 1 2 |
+-------------------------+--------------------+----------------------+
| 1 2458 7 |b58 6 a25 | 489 9-2 3 |
| 4568 24568 9 |b578 1 3 | 4678 c27 48 |
| 68 268 3 | 9 4 27 | 678 5 1 |
+-------------------------+--------------------+----------------------+
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Step 2: (2=516)r732c6 - (6=4587)r1378c4 = (7=2)r8c8 => - 2r7c8
Code: |
+-----------------------+--------------------+--------------------+
| 2 7 f456 |g456 9 8 | 1 3 45 |
| 456 9 1456 | 3 7 156 | 2 48 458 |
| 458 3 1458 | 45 2 15 | 9 7 6 |
+-----------------------+--------------------+--------------------+
| 3 1 e68 | 2 5 9 |e48 468 7 |
| 7 68 2 | 1 3 4 | 5 68 9 |
| 9 45 45 |h67 8 i67 | 3 1 2 |
+-----------------------+--------------------+--------------------+
| 1 c245 7 | 58 6 25 |d48 9 3 |
| 456 456 9 | 578 1 3 | 67 2 48 |
| 68 b268 3 | 9 4 ja7-2| 67 5 1 |
+-----------------------+--------------------+--------------------+
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Step 3: (2)r9c6 - r9c2 = (2-4)r7c2 = r7c7 - (4=86)r4c73 - (6)r1c3 = r1c4 - (6=7)r6c4 - r6c6 = (7)r9c6 => - 2r9c6; stte |
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immpy
Joined: 06 May 2017 Posts: 571
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Posted: Tue Apr 07, 2020 4:11 pm Post subject: |
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Yesss!! A beautiful use of the Sue de Coq, and I unfortunately missed it. I am thinking that because the 6 also got "locked" into the pattern, that any 6 in r7 and box9 (outside of the intersecting cells) could also have been eliminated. Not sure if this would have solved much further. I may bring this puzzle up again in my program to test this out. I absolutely LOVE the Sue de Coq and I don't like missing them. Superbly executed Clement.
cheers...immp |
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immpy
Joined: 06 May 2017 Posts: 571
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Posted: Tue Apr 07, 2020 4:33 pm Post subject: |
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Hello all,
I see now why I missed the Sue de Coq. It was no longer available due to the Naked Triple (468) in r245c8, which essentially made the same eliminations. Still a nice technique. I needed something similar to Clement's last two steps to solve as well.
cheers...immp |
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Clement
Joined: 24 Apr 2006 Posts: 1111 Location: Dar es Salaam Tanzania
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Posted: Tue Apr 07, 2020 7:47 pm Post subject: |
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immpy wrote: | Hello all,
I see now why I missed the Sue de Coq. It was no longer available due to the Naked Triple (468) in r245c8, which essentially made the same eliminations. Still a nice technique. I needed something similar to Clement's last two steps to solve as well.
cheers...immp | Your quite right "immmpy". Shame upon on me! I couldn't see the naked triple. |
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