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storm_norm
Joined: 18 Oct 2007
Posts: 1741
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 Posted: Sun Aug 08, 2010 10:36 pm Post subject: playr.co.uk/sudoku... extreme for august 8, 2010 |
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| Code: | . 4 .|. . .|. 3 .
. . .|2 8 3|. . .
. . 1|. 4 .|6 . .
-----+-----+-----
7 . .|6 5 9|. . 4
9 8 .|. . .|. 6 5
1 . .|8 7 4|. . 3
-----+-----+-----
. . 9|. 6 .|3 . .
. . .|3 2 7|. . .
. 5 .|. . .|. 2 . |
after basics
| Code: | +-------------------+-----------+-----------------+
| 258 4 278 | 79 1 6 | 59 3 2789 |
| 56 79 (67) | 2 8 3 | 459 1457 179 |
| 238 2379 1 | 79 4 5 | 6 78 2789 |
+-------------------+-----------+-----------------+
| 7 23 23 | 6 5 9 | 18 18 4 |
| 9 8 4 | 1 3 2 | 7 6 5 |
| 1 6 5 | 8 7 4 | 2 9 3 |
+-------------------+-----------+-----------------+
| 248 27 9 | 5 6 18 | 3 1478 178 |
| 468 1 8-6 | 3 2 7 | 459 458 689 |
| (36) 5 (367) | 4 9 18 | 18 2 67 |
+-------------------+-----------+-----------------+ |
#1...xyz-wing {3,6,7}; r8c3 <> 6
--------------
| Code: | +-----------------+-----------+------------------+
| 258 4 27 | 79 1 6 | 59 3 2789 |
| (56) 79 67 | 2 8 3 | 459 147-5 179 |
| 238 2379 1 | 79 4 5 | 6 78 2789 |
+-----------------+-----------+------------------+
| 7 23 23 | 6 5 9 | 18 18 4 |
| 9 8 4 | 1 3 2 | 7 6 5 |
| 1 6 5 | 8 7 4 | 2 9 3 |
+-----------------+-----------+------------------+
| 24 27 9 | 5 6 18 | 3 1478 178 |
| (46) 1 8 | 3 2 7 | 459 (45) 69 |
| 36 5 367 | 4 9 18 | 18 2 67 |
+-----------------+-----------+------------------+ |
#2...xy-wing {4,5,6}; r2c8 <> 5
--------------
| Code: | +--------------------+-----------+-----------------+
| 58(2) 4 7(2) | 79 1 6 | 59 3 2789 |
| 56 79 67 | 2 8 3 | 459 147 179 |
| 38(2) 2379 1 | 79 4 5 | 6 78 2789 |
+--------------------+-----------+-----------------+
| 7 23 (23) | 6 5 9 | 18 18 4 |
| 9 8 4 | 1 3 2 | 7 6 5 |
| 1 6 5 | 8 7 4 | 2 9 3 |
+--------------------+-----------+-----------------+
| (24) 27 9 | 5 6 18 | 3 1478 178 |
| -6(4) 1 8 | 3 2 7 | 49 5 69 |
| (36) 5 67(3) | 4 9 18 | 18 2 67 |
+--------------------+-----------+-----------------+ |
#3...(6=3)r9c1 - (3)r9c3 = (3-2)r4c3 = (2)r1c3 - (2)r13c1 = (2-4)r7c1 = (4)r8c1; r8c1 <> 6
singles from there.
---------------
after basics there is a nice deadly pattern in the 1's and 8's
the 1 and 8 can be removed from r7c8. |
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Mogulmeister
Joined: 03 May 2007
Posts: 1151
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| Posted: Mon Aug 09, 2010 1:51 am Post subject: |
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Fun puzzle Norm.
I played with creating ALS structures around the locked 23 pair at r4c23.
This one did it and I liked this because there was a double elimination needed.
Set A = {2,3,7}
Set B = {2,3,6,7,8}
x = 3 at r4c23
z = 7s at r23c2; r23c2<>7 solves.
| Code: | +-------------------+-------------------+-------------------+
| 258 4 B278 | 79 1 6 | 59 3 2789 |
| 56 9-7 B67 | 2 8 3 | 459 1457 179 |
| 238 239-7 1 | 79 4 5 | 6 78 2789 |
+-------------------+-------------------+-------------------+
| 7 A23 B23 | 6 5 9 | 18 18 4 |
| 9 8 4 | 1 3 2 | 7 6 5 |
| 1 6 5 | 8 7 4 | 2 9 3 |
+-------------------+-------------------+-------------------+
| 248 A27 9 | 5 6 18 | 3 1478 178 |
| 468 1 B68 | 3 2 7 | 459 458 1689 |
| 36 5 367 | 4 9 18 | 18 2 67 |
+-------------------+-------------------+-------------------+
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Mogulmeister
Joined: 03 May 2007
Posts: 1151
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| Posted: Mon Aug 09, 2010 2:13 am Post subject: |
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Alternatively you could see the 8 in r1c3 as the fin on an xy-chain (asterisked)
If the xy-chain is true then r23c2<>7
If the fin is true then (27=8)r1c3-(8=6)r8c3-(6=7)r2c3 and r23c2<>7
| Code: | +-------------------+-------------------+-------------------+
| 258 4 *27+8 | 79 1 6 | 59 3 2789 |
| 56 9-7 (6)7 | 2 8 3 | 459 1457 179 |
| 238 239-7 1 | 79 4 5 | 6 78 2789 |
+-------------------+-------------------+-------------------+
| 7 *23 *23 | 6 5 9 | 18 18 4 |
| 9 8 4 | 1 3 2 | 7 6 5 |
| 1 6 5 | 8 7 4 | 2 9 3 |
+-------------------+-------------------+-------------------+
| 248 *27 9 | 5 6 18 | 3 1478 178 |
| 468 1 6(8) | 3 2 7 | 459 458 1689 |
| 36 5 367 | 4 9 18 | 18 2 67 |
+-------------------+-------------------+-------------------+
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peterj
Joined: 26 Mar 2010
Posts: 974
Location: London, UK
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| Posted: Mon Aug 09, 2010 12:38 pm Post subject: |
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Roughly in the same area is this short discontinuous loop..
| Code: | | As an AIC, (2=3)r4c2 - r4c3=(3-7)r9c3=r7c2 ; r7c2<>2 |
Mm, you almost-xy-chain is also an almost w-wing! |
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Mogulmeister
Joined: 03 May 2007
Posts: 1151
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| Posted: Mon Aug 09, 2010 1:00 pm Post subject: |
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| I know, I nearly went "x-ey,y-ey,wing-ey thing-ey" ! They're all just AICs - I think I'm losing my religion. |
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Luke451
Joined: 20 Apr 2008
Posts: 310
Location: Southern Northern California
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| Posted: Tue Aug 10, 2010 5:17 am Post subject: |
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| Mogulmeister wrote: | | I know, I nearly went "x-ey,y-ey,wing-ey thing-ey" ! They're all just AICs - I think I'm losing my religion. |
You've been proselytized by the dark side  . |
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Mogulmeister
Joined: 03 May 2007
Posts: 1151
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| Posted: Tue Aug 10, 2010 7:28 am Post subject: |
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| Yes-get behind me Satan! |
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