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storm_norm
Joined: 18 Oct 2007 Posts: 1741
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Posted: Fri Mar 28, 2008 10:09 pm Post subject: competition #992 plus bonus |
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competition #992 from sudokulist.
Code: | ...|6..|4.1
..4|3..|8..
2..|...|3.5
---+---+---
1..|.25|.46
...|...|...
92.|46.|..3
---+---+---
6.3|...|..2
..2|..6|5..
5.9|..8|... |
for the fisherman, there is a jellyfish ( A.K.A. x-wing ^2 ) on the number 8 right after basics.
also of interest, two ER eliminations on 8.
----
this puzzle probaby contains eveything if you have time to look for it.
I think I count 1 xy-chain, coloring on 7, xy-wing, finned x-wing, ER, not in that order, don't want to spoil the fun.
Code: | 94.|.5.|8.3
..2|...|..1
1..|..4|.9.
---+---+---
..6|2.5|...
3..|.9.|..5
...|3.6|7..
---+---+---
.3.|9..|..2
5..|...|1..
7.1|.6.|.84 |
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I will throw this 9x7 monster in here for good measure. its extreme, and I couldn't solve it. it was rated fiendish on sudokupuzz.com, right !!
Code: | ...|...|...
.5.|1.7|.6.
.96|2.8|37.
---+---+---
9..|7.3|..8
..8|4.1|7..
2..|8.9|..4
---+---+---
.23|6.5|94.
.1.|3.4|.2.
...|...|... |
enjoy, |
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ravel
Joined: 21 Apr 2006 Posts: 536
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Posted: Sat Mar 29, 2008 1:18 pm Post subject: |
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The first two are nice M-wing puzzles.
The third one becomes very nice after this chain:
Code: | *-----------------------------------------------------------*
| 347 3478 247 | 5 39 6 | 124 189 129 |
| 348 5 24 | 1 39 7 | 48 6 29 |
| 1 9 6 | 2 4 8 | 3 7 5 |
|-------------------+-------------------+-------------------|
| 9 46 145 | 7 256 3 | 1256 15 8 |
|*356 *36 8 | 4 256 1 | 7 359 2-369 |
| 2 367 157 | 8 56 9 | 156 135 4 |
|-------------------+-------------------+-------------------|
| 78 2 3 | 6 178 5 | 9 4 17 |
|*5678 1 9 | 3 78 4 |*568 2 67 |
| 4567 4678 457 | 9 17 2 | 156 *1358 *367 |
*-----------------------------------------------------------* |
r5c12=36 or
r5c1=5 => r8c1<5> r8c7=5 => r9c8=8 => r9c9=3
==> r5c9<>3 |
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Victor
Joined: 29 Sep 2005 Posts: 207 Location: NI
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Posted: Sat Mar 29, 2008 11:33 pm Post subject: |
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First one, after the X-wing in 8s:
Code: |
+------------+----------------+------------+
| 3 589 58 | 6 5789 279 | 4 27 1 |
| 7 56 4 | 3 B15 12 | 8 26 9 |
| 2 689 1 | 79 4789 479 | 3 67 5 |
+------------+----------------+------------+
| 1 3 7 | 8 2 5 | 9 4 6 |
| 48 45 6 | 179 179 3 | 2 A15 78 |
| 9 2 58 | 4 6 17 | 17 58 3 |
+------------+----------------+------------+
| 6 1478 3 | 5 1479 1479 | 17 189 2 |
| 48 147 2 | 179 13479 6 | 5 139 478 |
| 5 147 9 | 2 1347 8 | 6 13 47 |
+------------+----------------+------------+
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More parallel universe stuff: I just can't see any M-wing as mentioned by Ravel. You can do this with a longish XY-chain but, searching for an M-wing, I noticed the following way to do it.
A <> 5 => B = 5 (considering 5s on their own - e.g. A & B are the free ends of a skyscraper)
But considering 1s: A = 1 => B = 1 (ER style). I.e. A <> 5 => B <> 5.
Ergo A <> 5 is false, etc. |
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Victor
Joined: 29 Sep 2005 Posts: 207 Location: NI
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Posted: Sat Mar 29, 2008 11:45 pm Post subject: |
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2nd one. After removing a 7 from r8c4 (colouring), an 8 from r7c5 (ER) & a 1 from r4c5 (UR):
Code: |
+------------+---------------+-----------+
| 9 4 7 | 16 5 12 | 8 26 3 |
| 68 568 2 | 678 3 9 | 4 57 1 |
| 1 568 3 | 678 278 4 | 256 9 67 |
+------------+---------------+-----------+
| 48 179 6 | 2 478 5 | 3 14 89 |
| 3 17 48 | 1478 9 178 | 26 26 5 |
| 2 19 5 | 3 148 6 | 7 14 89 |
+------------+---------------+-----------+
| 468 3 48 | 9 17 178 | 56 57 2 |
| 5 68 9 | 48 2478 278 | 1 3 67 |
| 7 2 1 | 5 6 3 | 9 8 4 |
+------------+---------------+-----------+
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Nice puzzle. The two lower 48s (boxes 7 & 8) are conjugate (because of an M-wing) and you can continue colouring in any direction in 8s to solve the puzzle .
Or, if you look at the two 17s in boxes 4 & 8, you can see ER-style via box 5 that they too are conjugate (i.e. one's a 1, the other's a 7) & so you can again continue colouring in any direction with either number. |
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ravel
Joined: 21 Apr 2006 Posts: 536
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Posted: Sun Mar 30, 2008 11:59 am Post subject: |
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In the first puzzle i saw the M-wing 15 connected by 4 strong links for 1.
But - oops - in the second puzzle i missed that the strong link for 4 in row 5 directly gives a w-wing 48 in r7c3 and r8c4, that solves the puzzle.
Instead i saw the pairs in r5c3 and r8c4 as M-wing (with strong link for 8 in column 3) to get to the same eliminations |
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Victor
Joined: 29 Sep 2005 Posts: 207 Location: NI
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Posted: Sun Mar 30, 2008 7:42 pm Post subject: |
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As you say, Ravel:
Quote: | In the first puzzle i saw the M-wing 15 connected by 4 strong links for 1. |
And I thought I was good at spotting these things! - thanks |
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