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Another L-O-N-G puzzle

 
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Victor



Joined: 29 Sep 2005
Posts: 207
Location: NI

PostPosted: Tue Apr 01, 2008 1:12 pm    Post subject: Another L-O-N-G puzzle Reply with quote

M6743041 (23)
Code:

+---------------+-------------+-----------+
| 137   4   2   | 18 1378 9   | 67 68  5  |
| 137   6   178 | 5  1378 178 | 4  9   2  |
| 59    59  78  | 4  6    2   | 1  3   78 |
+---------------+-------------+-----------+
| 147   27  9   | 6  17   5   | 8  124 3  |
| 14567 578 147 | 3  2    178 | 67 146 9  |
| 167   278 3   | 9  178  4   | 5  126 17 |
+---------------+-------------+-----------+
| 49    1   6   | 7  59   3   | 2  58  48 |
| 2     3   5   | 18 4    18  | 9  7   6  |
| 8     79  47  | 2  59   6   | 3  15  14 |
+---------------+-------------+-----------+

Play this puzzle online

Looks easy, and indeed it can be done with fairly straightforward moves - colouring / X(Y)-things / etc. It's just that I needed a LOT of moves: despite the plethora of flightless things etc., I couldn't see any really smart stuff. Ravel managed to cleverly shortcut a similar problem recently (where some people hadn't a chance because I'd made a posting mistake, which I haven't done here). Can anybody spot a quick way here?
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Marty R.



Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA

PostPosted: Tue Apr 01, 2008 3:47 pm    Post subject: Reply with quote

The XY-Wing 14-17-47 pivoted in r9c9, with pincer coloring, takes out two 7s from column 3, leaving us here:

Code:
+---------------+-------------+-----------+
| 137   4   2   | 18 1378 9   | 67 68  5  |
| 137   6   18  | 5  1378 178 | 4  9   2  |
| 59    59  78  | 4  6    2   | 1  3   78 |
+---------------+-------------+-----------+
| 147   27  9   | 6  17   5   | 8  124 3  |
| 14567 578 14  | 3  2    178 | 67 146 9  |
| 167   278 3   | 9  178  4   | 5  126 17 |
+---------------+-------------+-----------+
| 49    1   6   | 7  59   3   | 2  58  48 |
| 2     3   5   | 18 4    18  | 9  7   6  |
| 8     79  47  | 2  59   6   | 3  15  14 |
+---------------+-------------+-----------+

Now a W-Wing on 14 takes out the 4 in r9c3, but I didn't carry it through to see how far it takes you.
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Asellus



Joined: 05 Jun 2007
Posts: 865
Location: Sonoma County, CA, USA

PostPosted: Tue Apr 01, 2008 9:10 pm    Post subject: Reply with quote

Try as I will, I can't see that {14} W-Wing. The external strong link on <1> eludes me.

However, the two {14}s together with {17} at r6c9 form an M-Wing that removes <1>s from r5c8 and r6c1.
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Marty R.



Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA

PostPosted: Tue Apr 01, 2008 9:26 pm    Post subject: Reply with quote

Quote:
Try as I will, I can't see that {14} W-Wing.

I can't either. Brain dead. Embarassed
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Asellus



Joined: 05 Jun 2007
Posts: 865
Location: Sonoma County, CA, USA

PostPosted: Tue Apr 01, 2008 10:43 pm    Post subject: Reply with quote

This puzzle responds nicely to basic Medusa (no "extensions"). First, however, I used the Skyscraper on <7> in c67, followed by Coloring of <7> (which removes more <7>s in r5c23 and r6c1).

Then, leaving the <7> coloring in place, expand into Medusa:
Code:
+---------------------+-------------------+---------------------+
| 137A   4      2     | 18   138    9     | 6A7a   6a8A   5     |
| 13     6      1A8a  | 5   #137-8  178   | 4      9      2     |
| 5a9A   5A9a   7a8A  | 4    6      2     | 1      3      7A8a  |
+---------------------+-------------------+---------------------+
| 147    27     9     | 6    17     5     | 8      124    3     |
| 145A67 5a8A   1a4A  | 3    2      178a  | 6a7A  #-146   9     |
|#-16    278a   3     | 9    178A   4     | 5      126    1A7a  |
+---------------------+-------------------+---------------------+
| 4A9a   1      6     | 7    5a9A   3     | 2      5A8a   4a8A  |
| 2      3      5     | 18   4      18    | 9      7      6     |
| 8      7a9A   4a7A  | 2    5A9a   6     | 3      1A5a   1a4A  |
+---------------------+-------------------+---------------------+

Eliminations are located in the cells marked #. Not surprisingly, those M-Wing <1>s go quickly. Continuing...
Code:
+--------------------+------------------+--------------------+
| 137A   4     2     | 18  138    9     | 6A7a  6a8A   5     |
| 13     6     1A8a  | 5   137    178A  | 4     9      2     |
| 5a9A   5A9a  7a8A  | 4   6      2     | 1     3      7A8a  |
+--------------------+------------------+--------------------+
|#14a-7  27    9     | 6   17     5     | 8     124A   3     |
|#1-45A7 5a8A  1a4A  | 3   2      178a  | 6a7A  4a6A   9     |
| 6      278a  3     | 9   178A   4     | 5     12     1A7a  |
+--------------------+------------------+--------------------+
| 4A9a   1     6     | 7   5a9A   3     | 2     5A8a   4a8A  |
| 2      3     5     | 18  4     #1-8   | 9     7      6     |
| 8      7a9A  4a7A  | 2   5A9a   6     | 3     1A5a   1a4A  |
+--------------------+------------------+--------------------+

After these eliminations, we find a Medusa Wrap:
Code:
+-------------------+----------------+------------------+
| 3a7A   4     2    | 1  3A8a   9    | 6A7a  6a8A  5    |
| 1a3A   6     1A8a | 5  3a7A   7a8A | 4     9     2    |
| 5a9A   5A9a  7a8A | 4  6      2    | 1     3     7A8a |
+-------------------+----------------+------------------+
| 14a    27    9    | 6  17     5    | 8     124A  3    |
| 15A7a  5a8A  1a4A | 3  2     @7A8a |@6a7A  4a6A  9    |
| 6      278a  3    | 9  178A   4    | 5     12    1A7a |
+-------------------+----------------+------------------+
| 4A9a   1     6    | 7  5a9A   3    | 2     5A8a  4a8A |
| 2      3     5    | 8  4      1    | 9     7     6    |
| 8      7a9A  4a7A | 2  5A9a   6    | 3     1A5a  1a4A |
+-------------------+----------------+------------------+

Row 5 contains two "A" <7>s, marked @. So, all "A" values are false and all "a" values are true.
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Johan



Joined: 25 Jun 2007
Posts: 206
Location: Bornem Belgium

PostPosted: Wed Apr 02, 2008 1:49 am    Post subject: Reply with quote

Needed five steps for this one
First an ER <7> in Box 5 takes out <7> in R1C5 and opens up a Finned x-wing
Code:
+-------------------------+-------------------------+------------------------+
| 137       4        2    | 18       13-[7]8   9    | 67       68        5   |
| 137       6        178  | 5        1378      178  | 4        9         2   |
| 59        59       78   | 4        6         2    | 1        3         78  |
+-------------------------+-------------------------+------------------------+
| 147       27       9    | 6 er     17        5 er | 8        124       3   |
| 14567     578      147  | 3        2         178  | 67       146       9   |
| 167       278      3    | 9 er     178       4 er | 5        126       17  |
+-------------------------+-------------------------+------------------------+
| 49        1        6    | 7        59        3    | 2        58        48  |
| 2         3        5    | 18       4         18   | 9        7         6   |
| 8         79       47   | 2        59        6    | 3        15        14  |
+-------------------------+-------------------------+------------------------+

The *Finned x-wing eliminates both <7>'s in R5C23
Code:
+-------------------------+-------------------------+------------------------+
|*137       4        2    | 18       138       9    |*67       68        5   |
| 13        6        18   | 5        1378      178  | 4        9         2   |
| 59        59       78   | 4        6         2    | 1        3         78  |
+-------------------------+-------------------------+------------------------+
|F147       27       9    | 6        17        5    | 8        124       3   |
|*14567     5-78     14-7 | 3        2         178  |*67       146       9   |
|F167       278      3    | 9        178       4    | 5        126       17  |
+-------------------------+-------------------------+------------------------+
| 49        1        6    | 7        59        3    | 2        58        48  |
| 2         3        5    | 18       4         18   | 9        7         6   |
| 8         79       47   | 2        59        6    | 3        15        14  |
+-------------------------+-------------------------+------------------------+

Then M-wing {14} pair(a,c) connected with the strong link(b) on <4> extended with <1> to R6C9(d) eliminating <1> in R5C8 and R6C1
Code:
+-------------------------+-------------------------+------------------------+
| 137       4        2    | 18       138       9    | 67       68        5   |
| 13        6        18   | 5        1378      178  | 4        9         2   |
| 59        59       78   | 4        6         2    | 1        3         78  |
+-------------------------+-------------------------+------------------------+
| 147       27       9    | 6        17        5    | 8        124       3   |
| 14567     58     a 14   | 3        2         178  | 67     -[1]46      9   |
|-[1]67     278      3    | 9        178       4    | 5        126     d 17  |
+-------------------------+-------------------------+------------------------+
| 49        1        6    | 7        59        3    | 2        58        48  |
| 2         3        5    | 18       4         18   | 9        7         6   |
| 8         79     b 47   | 2        59        6    | 3        15      c 14  |
+-------------------------+-------------------------+------------------------+

The fourth step a 6-cell xy-chain with pincer ends at R8C6(A) and R5C3(F), that takes out <1> in R5C6
Code:
+-------------------------+-------------------------+------------------------+
| 137       4        2    | 18 C     138       9    | 67     D 68        5   |
| 13        6        18   | 5        1378      178  | 4        9         2   |
| 59        59       78   | 4        6         2    | 1        3         78  |
+-------------------------+-------------------------+------------------------+
| 147       27       9    | 6        17        5    | 8        124       3   |
| 14567     58     F 14   | 3        2       -[1]78 | 67     E 46        9   |
| 67        278      3    | 9        178       4    | 5        126       17  |
+-------------------------+-------------------------+------------------------+
| 49        1        6    | 7        59        3    | 2        58        48  |
| 2         3        5    | 18 B     4       A 18   | 9        7         6   |
| 8         79       47   | 2        59        6    | 3        15        14  |
+-------------------------+-------------------------+------------------------+

Finally @xy-wing with pivot in R7C1 solves the puzzle
Code:
+-------------------------+-------------------------+------------------------+
| 137       4        2    | 18       138       9    | 67       68        5   |
| 13        6        18   | 5        1378      178  | 4        9         2   |
| 59        59       78   | 4        6         2    | 1        3         78  |
+-------------------------+-------------------------+------------------------+
|@47        27       9    | 6        17        5    | 8        124       3   |
| 14567     58       14   | 3        2         78   | 67       46        9   |
| 67        278      3    | 9        178       4    | 5        126       17  |
+-------------------------+-------------------------+------------------------+
|@49        1        6    | 7        59        3    | 2        58        48  |
| 2         3        5    | 18       4         18   | 9        7         6   |
| 8        @79       47   | 2        59        6    | 3        15        14  |
+-------------------------+-------------------------+------------------------+

Thx Victor nice puzzle
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ravel



Joined: 21 Apr 2006
Posts: 536

PostPosted: Wed Apr 02, 2008 8:46 am    Post subject: Reply with quote

As an alternative to Johan's xy-chain you can use the UR 13:
Code:
 *------------------------------------------------*
 |#137   4    2   | 18 #138   9    | 67  68   5   |
 |#13    6    18  | 5  #1378  178  | 4   9    2   |
 | 59    59   78  | 4   6     2    | 1   3    78  |
 |----------------+----------------+--------------|
 | 147   27   9   | 6   17    5    | 8   124  3   |
 | 1457  578  14  | 3   2     178  | 67  146  9   |
 | 6     278  3   | 9   178   4    | 5   12   17  |
 |----------------+----------------+--------------|
 | 49    1    6   | 7   59    3    | 2   58   48  |
 | 2     3    5   | 18  4     18   | 9   7    6   |
 | 8     79   47  | 2   59    6    | 3   15   14  |
 *------------------------------------------------*

There is a x-wing for 3, so the 1 in r1c5 goes directly, and the 1 in r2c5 with the link r2c5=1 => r1c45<>1 => r1c1=1.
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Victor



Joined: 29 Sep 2005
Posts: 207
Location: NI

PostPosted: Wed Apr 02, 2008 5:10 pm    Post subject: Reply with quote

I'm impressed, folks! I like to think that I'm quite good at this kind of puzzle, but in fact I got kind of bogged down & took too long to finish - couldn't see the trees for the wood.
PS glad to see, Marty, that I'm not the only person capable of making silly mistakes.
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storm_norm



Joined: 18 Oct 2007
Posts: 1741

PostPosted: Mon Apr 07, 2008 11:01 pm    Post subject: Reply with quote

victor,

I have another LONG one for your collection. there is also a 12 cell xy-chain present at some point along the way.

Code:
...|7..|5..
3.5|.8.|.1.
2..|3..|8..
---+---+---
..9|.48|..1
.6.|...|.9.
4..|92.|7..
---+---+---
..6|..1|..9
.2.|.6.|1.8
..4|..7|...


good luck
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Victor



Joined: 29 Sep 2005
Posts: 207
Location: NI

PostPosted: Mon Apr 07, 2008 11:17 pm    Post subject: Reply with quote

Thanks Norm, I'll have a go tomorrow.
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ravel



Joined: 21 Apr 2006
Posts: 536

PostPosted: Tue Apr 08, 2008 10:16 am    Post subject: Reply with quote

Storm_norm's puzzle:

UR 79 in r13c26 pinned 9 to r1c2 and r3c6
Code:
 *------------------------------------------------*
 | 6   9     8   | 7   1 #24   | 5    234   234   |
 | 3   47    5   | 46  8  246  | 9    1     247   |
 | 2   147   17  | 3   5  9    | 8    46    467   |
 |---------------+-------------+------------------|
 | 57  357   9   | 56  4  8    | 236  2356  1     |
 | 8   6     2   | 1   7  35   | 34   9     345   |
 | 4   135   13  | 9   2  356  | 7    8     356   |
 |---------------+-------------+------------------|
 | 57  578   6   | 28  3  1    |#24   2457  9     |
 | 9   2     37  | 45  6  45   | 1    37    8     |
 | 1   358   4   | 28  9  7    | 236  2356  2356  |
 *------------------------------------------------*
The pair 24:
r1c6=4 => r8c6=5 => r5c6=3 => r5c7=4 => r7c7=2
r1c6=2 => r2c46=46 => r2c2=7 => r8c3=7 => r8c8=3 => r9c789=256 => r7c7=4.
So one of them is 2 and one is 4.
r7c7=4 => r6c9=4 ==> r1c9<>4
r1c6=2 => r2c9=2 ==> r9c9<>2
r7c7=2 => r3c8=2 ==> r1c8<>2
Code:
 *----------------------------------------------*
 | 6   9    8   | 7   1  24   | 5   #34    23   |
 | 3   47   5   | 46  8  246  | 9    1     247  |
 | 2   147  17  | 3   5  9    | 8    46    467  |
 |--------------+-------------+-----------------|
 | 57  357  9   | 56  4  8    | 236  2356  1    |
 | 8   6    2   | 1   7  35   |#34   9     345  |
 | 4   135  13  | 9   2  356  | 7    8     356  |
 |--------------+-------------+-----------------|
 | 57  578  6   | 28  3  1    | 24   2457  9    |
 | 9   2    37  | 45  6  45   | 1    37    8    |
 | 1   358  4   | 28  9  7    | 236  2356  356  |
 *----------------------------------------------*
The pair 34:
r1c8=4 => r7c7=4 => r5c7=3
r1c8=3 => r1c6=4 => r8c6=5 => r5c6=3 => r5c7=4
So this is a remote pair also where one must be 3 and one 4
r5c7=3 => r6c6=3 => r4c2=3 => r8c3=3 ==> r48c8<>3
r5c7=4 => r7c8=4 ==> r3c8<>4

Remark: Thanks for that, storm_norm. Of course these chains are rather long. But when you know where you want to get to and it is there, it does not take much time. Because i like to use the pairs, this was not a very long puzzle for me.
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Asellus



Joined: 05 Jun 2007
Posts: 865
Location: Sonoma County, CA, USA

PostPosted: Tue Apr 08, 2008 5:41 pm    Post subject: Reply with quote

First...
ravel wrote:
r7c7=2 => r3c8=2 ==> r1c8<>2

For those trying to follow, that should be:
r7c7=2 => r4c8=2 ==> r1c8<>2

Here is a shorter solution from ravel's first grid:

(3-6)r6c6=(6)r2c6-(6=4)r2c4-(4)r2c2=(4-1)r3c2=(1)r6c2-(1=3)r6c3-(3)r6c6; r6c6<>3

This solves the puzzle.

In ravel's way of writing it:
r6c6=3 => r2c6=6 => r2c4=4 => r3c2=4 => r6c2=1 => r6c3=3 ==> r6c6<>3
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Victor



Joined: 29 Sep 2005
Posts: 207
Location: NI

PostPosted: Tue Apr 08, 2008 8:30 pm    Post subject: Reply with quote

First time round, I did indeed need long chains, including a 12-step one. But I tried again & found a single chain that does it. Guess it shows (yet again) that there's some luck involved. There's an XY-chain from the 3 of r5c6 to the 3 of r6c1: 35-56-64-47-71-13, & that's enough to solve the puzzle, whether or not you've done the UR eliminations in r13: gives r6c6 <> 3, as in the chain given by Asellus.

PS: Ravel, glad to see that I'm not alone in writing carelessly: you wrote "79" instead of "49". I do of course like using the conjugate 24s.
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storm_norm



Joined: 18 Oct 2007
Posts: 1741

PostPosted: Tue Apr 08, 2008 8:35 pm    Post subject: Reply with quote

I like to look for ways around the xy-chain without having to look at every cell around the board and you guys gave me a way to do that, thanx.
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