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Earl
Joined: 30 May 2007
Posts: 677
Location: Victoria, KS
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 Posted: Sun Dec 23, 2007 10:39 pm Post subject: Dec 22 DB |
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[Edit by keith to place original puzzle at start of thread]
| Code: | +-------+-------+-------+
| . . . | . 8 . | . 4 3 |
| . 5 6 | . . . | 9 . 2 |
| . . . | . . 2 | . 6 . |
+-------+-------+-------+
| . . 5 | . . 3 | . . . |
| 4 . . | 2 . 9 | . . 1 |
| . . . | 4 . . | 2 . . |
+-------+-------+-------+
| . 8 . | 3 . . | . . . |
| 9 . 4 | . . . | 5 1 . |
| 2 6 . | . 7 . | . . . |
+-------+-------+-------+
|
[end edit]
The Dec 22 DB after basics:
I needed two xy- chains. One with pincers at R4C1 and R6C9, eliminates 6's. The other has pincers at R2C5 and R6C1, eliminates 3 in R2C1 and opens the puzzle. Any neater solutions?
Earl
| Code: |
+-----------+---------------+----------------+
| 17 9 2 | 1567 8 567 | 17 4 3 |
| 1378 5 6 | 17 34 47 | 9 78 2 |
| 1378 4 38 | 179 39 2 | 178 6 5 |
+-----------+---------------+----------------+
| 68 2 5 | 678 1 3 | 4678 789 4689 |
| 4 7 38 | 2 56 9 | 368 358 1 |
| 368 1 9 | 4 56 5678 | 2 3578 68 |
+-----------+---------------+----------------+
| 5 8 7 | 3 469 1 | 46 2 469 |
| 9 3 4 | 68 2 68 | 5 1 7 |
| 2 6 1 | 589 7 458 | 348 389 489 |
+-----------+---------------+----------------+
|
Play this puzzle online at the Daily Sudoku site |
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Johan
Joined: 25 Jun 2007
Posts: 206
Location: Bornem Belgium
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| Posted: Mon Dec 24, 2007 12:17 am Post subject: |
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Another step to solve this one is when R3C5=3, then R1C3=8, which results in a [17] DP in R13C17, so R3C5 can't be <3> but must be <9>, solving the puzzle.
The grid after the naked pairs [17] in R1, [68] in Box 8 and the [56] pair in Box 5
| Code: |
+--------------------------+--------------------------+--------------------------+
|*17 9 2 | 56 8 56 |*17 4 3 |
| 1378 5 6 | 17 34 47 | 9 78 8 |
|*1378 4 38 | 179 39 2 |*178 6 5 |
+--------------------------+--------------------------+--------------------------+
| 68 2 5 | 78 1 3 | 4678 789 4689 |
| 4 7 38 | 2 56 9 | 368 358 1 |
| 368 1 9 | 4 56 78 | 2 3578 68 |
+--------------------------+--------------------------+--------------------------+
| 5 8 7 | 3 49 1 | 46 2 469 |
| 9 3 4 | 68 2 68 | 5 1 7 |
| 2 6 1 | 59 7 45 | 348 389 489 |
+--------------------------+--------------------------+--------------------------+
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Asellus
Joined: 05 Jun 2007
Posts: 865
Location: Sonoma County, CA, USA
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| Posted: Mon Dec 24, 2007 12:17 am Post subject: |
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Earl,
You might want to take advantage of some of those naked pairs first. Then, your grid will look like this:
| Code: | +-----------+---------------+----------------+
| 17 9 2 | 56 8 56 | 17 4 3 |
| 1378 5 6 | 17 34 47 | 9 78 2 |
| 1378 4 38 | 179 39 2 | 178 6 5 |
+-----------+---------------+----------------+
| 68 2 5 | 78 1 3 | 4678 789 4689 |
| 4 7 38 | 2 56 9 | 368 358 1 |
| 368 1 9 | 4 56 78 | 2 3578 68 |
+-----------+---------------+----------------+
| 5 8 7 | 3 49 1 | 46 2 469 |
| 9 3 4 | 68 2 68 | 5 1 7 |
| 2 6 1 | 59 7 45 | 348 389 489 |
+-----------+---------------+----------------+ |
Next, you might want to take a look at the "a little help please" thread posted by stef in the "Daily Sudoku puzzles" forum. |
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Asellus
Joined: 05 Jun 2007
Posts: 865
Location: Sonoma County, CA, USA
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| Posted: Mon Dec 24, 2007 12:19 am Post subject: |
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Johan,
Have you been reading stef's thread?  |
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Johan
Joined: 25 Jun 2007
Posts: 206
Location: Bornem Belgium
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| Posted: Mon Dec 24, 2007 12:34 am Post subject: |
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| Quote: | Johan,
Have you been reading stef's thread? |
Asellus,
Now I did, it looks like Gemini  |
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Mon Dec 24, 2007 12:55 am Post subject: |
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| Earl, do you have the original? |
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Earl
Joined: 30 May 2007
Posts: 677
Location: Victoria, KS
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| Posted: Wed Dec 26, 2007 3:17 pm Post subject: Dec 22 BD |
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As requested, here is the Dec 22 DB original:
Earl
| Code: |
+-------+-------+-------+
| . . . | . 8 . | . 4 3 |
| . 5 6 | . . . | 9 . 2 |
| . . . | . . 2 | . 6 . |
+-------+-------+-------+
| . . 5 | . . 3 | . . . |
| 4 . . | 2 . 9 | . . 1 |
| . . . | 4 . . | 2 . . |
+-------+-------+-------+
| . 8 . | 3 . . | . . . |
| 9 . 4 | . . . | 5 1 . |
| 2 6 . | . 7 . | . . . |
+-------+-------+-------+
|
Play this puzzle online at the Daily Sudoku site |
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Wed Dec 26, 2007 7:08 pm Post subject: |
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Thanks Earl.
| Johan wrote: | Another step to solve this one is when R3C5=3, then R1C3=8, which results in a [17] DP in R13C17, so R3C5 can't be <3> but must be <9>, solving the puzzle.
The grid after the naked pairs [17] in R1, [68] in Box 8 and the [56] pair in Box 5
| Code: |
+--------------------------+--------------------------+--------------------------+
|*17 9 2 | 56 8 56 |*17 4 3 |
| 1378 5 6 | 17 34 47 | 9 78 8 |
|*1378 4 38 | 179 39 2 |*178 6 5 |
+--------------------------+--------------------------+--------------------------+
| 68 2 5 | 78 1 3 | 4678 789 4689 |
| 4 7 38 | 2 56 9 | 368 358 1 |
| 368 1 9 | 4 56 78 | 2 3578 68 |
+--------------------------+--------------------------+--------------------------+
| 5 8 7 | 3 49 1 | 46 2 469 |
| 9 3 4 | 68 2 68 | 5 1 7 |
| 2 6 1 | 59 7 45 | 348 389 489 |
+--------------------------+--------------------------+--------------------------+
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Another way to solve r3c5 is to use what Keith's rectangle writeup calls a "reduced set." In the 17 rectangle, r3c1 must be 3 or 8 or r3c7 must be 8. So we have those two cells needing a 3 or 8. They combine with the 38 in r3c3 to act as a naked pair and exclude 3 from r3c5. |
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keith
Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
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