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keith
Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
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 Posted: Fri Jan 09, 2009 5:36 pm Post subject: Free Press, Jan 9, 2009 |
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| Code: | Puzzle: FP010909
+-------+-------+-------+
| 1 . . | . . . | . . . |
| . 3 6 | . 5 . | 8 . . |
| 7 . . | . 9 . | . 5 2 |
+-------+-------+-------+
| 3 . . | 9 6 . | . 7 . |
| . . . | . . . | . . . |
| . 2 4 | . 7 8 | . . 3 |
+-------+-------+-------+
| 4 9 . | . 1 . | . . 8 |
| . . 5 | . 8 . | 3 9 . |
| . . . | . . . | . . 1 |
+-------+-------+-------+ |
| Quote: | | Not yet solved, but it seems that after only nine singles, you need a chain. |
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storm_norm
Joined: 18 Oct 2007
Posts: 1741
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| Posted: Fri Jan 09, 2009 6:29 pm Post subject: |
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Keith,
wonder if the editors looked at this one as carefully as they could. is there precedence for this difficulty in the freep?
I got a multi-coloring on 9 first. then... 
ok, back...
found a m-wing with group ending...
| Code: | .------------------------.------------------------.------------------------.
| 1 5 29 | 8 24 2467 | 467 3 4679 |
| 29 3 6 | 1247 5 1247 | 8 *14 479 |
| 7 4 8 | 136 9 136 |*16 5 2 |
:------------------------+------------------------+------------------------:
| 3 8 1 | 9 6 245 | 24 7 45 |
| 569 67 79 | 12345 234 12345 | 1246 8 456 |
| 569 2 4 | 15 7 8 | 169 *16 3 |
:------------------------+------------------------+------------------------:
| 4 9 237 | 23567 1 23567 |5-67 *26 8 |
| 26 1 5 | 2467 8 2467 | 3 9 467 |
| 8 67 237 | 234567 234 9 |45-67 *246 1 |
'------------------------'------------------------'------------------------' |
M-wing {1,6} the group of 6's in box 9 {r79c8} are true or the 6 in r3c7 is true, eliminates the 6's in r79c7
(6=1)r3c7 - (1)r2c8 = (1-6)r6c8 = (6)r79c8; r79c7 <> 6 |
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storm_norm
Joined: 18 Oct 2007
Posts: 1741
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| Posted: Fri Jan 09, 2009 9:42 pm Post subject: |
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| Code: | .------------------------.------------------------.------------------------.
| 1 5 29 | 8 24 2467 | 467 3 4679 |
| 29 3 6 | 1247 5 1247 | 8 14 479 |
| 7 4 8 | 136 9 136 | 16 5 2 |
:------------------------+------------------------+------------------------:
| 3 8 1 | 9 6 245 | 24 7 45 |
| 569 67 79 | 12345 234 12345 | 1246 8 456 |
| 569 2 4 | 15 7 8 | 169 16 3 |
:------------------------+------------------------+------------------------:
| 4 9 237 | 23567 1 23567 | 57 26 8 |
| 26 1 5 | 2467 8 2467 | 3 9 467 |
| 8 67 237 | 234567 234 9 | 457 246 1 |
'------------------------'------------------------'------------------------' |
(4=2)r1c5 - (2)r1c3 = (2)r2c1 - (2=6)r8c1 - (6)r8c9 = (6)r79c8 - (6=1)r6c8 - (1=4)r2c8; r2c46|r1c79 <> 4
| Code: | .------------------------.------------------------.------------------------.
| 1 5 29 | 8 24 2467 | 67 3 679 |
| 29 3 6 | 127 5 127 | 8 14 479 |
| 7 4 8 | 136 9 136 | 16 5 2 |
:------------------------+------------------------+------------------------:
| 3 8 1 | 9 6 245 | 24 7 45 |
| 569 67 79 | 12345 234 12345 | 1246 8 456 |
| 569 2 4 | 15 7 8 | 169 16 3 |
:------------------------+------------------------+------------------------:
| 4 9 237 | 23567 1 23567 | 57 26 8 |
| 26 1 5 | 2467 8 2467 | 3 9 467 |
| 8 67 237 | 234567 234 9 | 457 246 1 |
'------------------------'------------------------'------------------------' |
(5=1)r6c4 - (1)r6c8 = (1-4)r2c8 = (4)r2c9 - (4=5)r4c9; r4c6 <> 5
this places 5 in r4c9
| Code: | .------------------------.------------------------.------------------------.
| 1 5 29 | 8 24 2467 | 67 3 679 |
| 29 3 6 | 127 5 127 | 8 14 479 |
| 7 4 8 | 136 9 136 | 16 5 2 |
:------------------------+------------------------+------------------------:
| 3 8 1 | 9 6 24 | 24 7 5 |
| 569 67 79 | 12345 234 12345 | 1246 8 46 |
| 569 2 4 | 15 7 8 | 169 16 3 |
:------------------------+------------------------+------------------------:
| 4 9 237 | 23567 1 23567 | 57 26 8 |
| 26 1 5 | 2467 8 2467 | 3 9 467 |
| 8 67 237 | 234567 234 9 | 457 246 1 |
'------------------------'------------------------'------------------------' |
xy-wing {1,4,6} in columns 8 and 9
I believe that finishes it. |
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daj95376
Joined: 23 Aug 2008
Posts: 3854
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| Posted: Fri Jan 09, 2009 11:30 pm Post subject: |
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Nothing spectacular -- other than stealing Norm's grouped M-Wing.
Obviously, I used my solver. (Initial Singles included because of Keith's comment.)
| Code: | 5x Naked Singles
6x Hidden Singles
c7b6 Locked Candidate 1 <> 2 [r79c7]
c7b9 Locked Candidate 1 <> 5 [r456c7]
r26 Skyscraper <> 9 [r1c7],[r5c9]
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| Code: | Norm's grouped M-Wing <> 6 [r79c7] excellent!
+--------------------------------------------------------------------------------+
| 1 5 29 | 8 24 2467 | 467 3 4679 |
| 29 3 6 | 1247 5 1247 | 8 *14 479 |
| 7 4 8 | 136 9 136 | *16 5 2 |
|--------------------------+--------------------------+--------------------------|
| 3 8 1 | 9 6 245 | 24 7 45 |
| 569 67 79 | 12345 234 12345 | 12469 8 456 |
| 569 2 4 | 15 7 8 | 169 *16 3 |
|--------------------------+--------------------------+--------------------------|
| 4 9 237 | 23567 1 23567 | 57-6 #26 8 |
| 26 1 5 | 2467 8 2467 | 3 9 467 |
| 8 67 237 | 234567 234 9 | 457-6 #246 1 |
+--------------------------------------------------------------------------------+
# 92 eliminations remain
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| Code: | (4)r9c8 = (4-1)r2c8 = (1)r6c8 - (1=5)r6c4 - (5)r9c4 = (5)r9c7 => [r9c7]<>4
+--------------------------------------------------------------------------------+
| 1 5 29 | 8 24 2467 | 467 3 4679 |
| 29 3 6 | 1247 5 1247 | 8 14 479 |
| 7 4 8 | 136 9 136 | 16 5 2 |
|--------------------------+--------------------------+--------------------------|
| 3 8 1 | 9 6 245 | 24 7 45 |
| 569 67 79 | 12345 234 12345 | 12469 8 456 |
| 569 2 4 | 15 7 8 | 169 16 3 |
|--------------------------+--------------------------+--------------------------|
| 4 9 237 | 23567 1 23567 | 57 26 8 |
| 26 1 5 | 2467 8 2467 | 3 9 467 |
| 8 67 237 | 234567 234 9 | 57-4 246 1 |
+--------------------------------------------------------------------------------+
# 90 eliminations remain
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| Code: | c7b9 Naked Pair <> 57 [r8c9]
c7b9 Naked Pair <> 57 [r1c7]
b3 Naked Triple <> 146 [r12c9] -or-
c9 Naked Triple <> 456 [r12c9]
c7b3 Locked Candidate 1 <> 6 [r56c7]
r8 b8 Locked Candidate 2 <> 7 [r7c46],[r9c4]
c29 Skyscraper <> 6 [r8c1],[r9c8]
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Asellus
Joined: 05 Jun 2007
Posts: 865
Location: Sonoma County, CA, USA
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| Posted: Sat Jan 10, 2009 12:58 am Post subject: |
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Norm's M-Wing based elimination of <6>s can also be seen as an ALS elimination:
(6=1)r3c7 - ALSr279c8[(1)r2c8=(6)r79c8]; r79c7<>6
There is another ALS elimination nearby:
ALS[(4)r2c8=(6)r6c8] - ALS[(6)r5c9=(4)r45c9]; r12c9<>4
But, recourse to Medusa Multi-coloring (MMC) was still needed. I found an AIC similar to Danny's:
(7-4)r1c7=(4-1)r2c8=(1)r6c8 - (1=5)r6c4 - (5)r9c4=(5)r9c7 - (5=7)r7c7 - (7)r1c7; r1c7<>7
After this, there was a Kite on 6 in r6 and c9 that finished it off. So, together with the initial 9 Skyscraper, it was 4 steps. But, the apparent requirement for multicluster MMC took this one way beyond newspaper level. |
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Sat Jan 10, 2009 2:02 am Post subject: |
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| I needed two rounds of Extended Medusa. |
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wapati
Joined: 10 Jun 2008
Posts: 472
Location: Brampton, Ontario, Canada.
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| Posted: Sat Jan 10, 2009 8:10 am Post subject: |
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Given the likely-hood that a given was left out, one that repairs symmetry is the 2 in r4c7. This does not leave an typical newspaper puzzle but does make it closer to believable.
| Code: | 1 . .|. . .|. . .
. 3 6|. 5 .|8 . .
7 . .|. 9 .|. 5 2
-----+-----+-----
3 . .|9 6 .|2 7 .
. . .|. . .|. . .
. 2 4|. 7 8|. . 3
-----+-----+-----
4 9 .|. 1 .|. . 8
. . 5|. 8 .|3 9 .
. . .|. . .|. . 1 |
Adding the r5c5 2 makes this a 3 stepper. The skyscraper on 9s, the noted m-wing (or the ALS doing the same job) and then an xy-chain or ALS again doing the same elimination. This is still odd for a newspaper puzzle. Curious! |
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keith
Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
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| Posted: Sat Jan 10, 2009 2:36 pm Post subject: |
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| wapati wrote: | | Given the likely-hood that a given was left out, one that repairs symmetry is the 2 in r4c7. |
Nothing was left out - I gave the puzzle as published.
Keith |
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wapati
Joined: 10 Jun 2008
Posts: 472
Location: Brampton, Ontario, Canada.
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| Posted: Sat Jan 10, 2009 3:31 pm Post subject: |
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| keith wrote: | | wapati wrote: | | Given the likely-hood that a given was left out, one that repairs symmetry is the 2 in r4c7. |
Nothing was left out - I gave the puzzle as published.
Keith |
 I am guessing that the newspaper intended to print a symmetric puzzle, and probably an easier one than appeared. |
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Sat Jan 10, 2009 4:40 pm Post subject: |
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| Quote: | | I am guessing that the newspaper intended to print a symmetric puzzle, and probably an easier one than appeared. |
Anything's possible, but the last two puzzles (Jan. 2 and Dec. 26) were asymmetrical. |
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storm_norm
Joined: 18 Oct 2007
Posts: 1741
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| Posted: Sat Jan 10, 2009 7:20 pm Post subject: |
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| wapati wrote: | | keith wrote: | | wapati wrote: | | Given the likely-hood that a given was left out, one that repairs symmetry is the 2 in r4c7. |
Nothing was left out - I gave the puzzle as published.
Keith |
I am guessing that the newspaper intended to print a symmetric puzzle, and probably an easier one than appeared. |
I'd put my money on the prospect that a hard puzzle thrown in every once in a while will generate enough curiosity for a few more paper sales. or hits on the site 
AND, the editor unsure/ignoring the difficulty altogether
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keith
Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
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| Posted: Sat Jan 10, 2009 8:53 pm Post subject: |
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It turns out that the LA Times puts these online. Check it out.
http://games.latimes.com/index_sudoku.html?uc_feature_code=lasud&uc_full_date=20090109
I will ask them what the source of the puzzles is.
I have noticed that these are usually not quite symmetric.
By the way, the last time I looked, the Free Press does not put their Sudoku online. Their site actually directs people to this site for online puzzles.
Keith |
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wapati
Joined: 10 Jun 2008
Posts: 472
Location: Brampton, Ontario, Canada.
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| Posted: Sun Jan 11, 2009 6:31 am Post subject: |
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I have been looking at the LA site and they do post some hard puzzles. Very few of their puzzles have symmetry.
Here is one from Dec. 26th.
http://games.latimes.com/index_sudoku.html?uc_feature_code=lasud&uc_full_date=20081226
| Code: | 6 . 7|. . .|. . 5
9 . .|. 2 .|. 7 .
. . 3|. . .|2 . .
-----+-----+-----
4 . .|5 . .|. . 9
. . .|. 1 .|. . .
7 . .|. 3 9|. . 4
-----+-----+-----
. . 5|. . .|6 . .
. 9 .|. 7 .|. 8 3
1 . .|. . .|5 . 2 |
I needed a 4-cell xy-chain and a skyscraper.
One solver I put it into suggested: 3 XY-Wings, 1 Hidden Unique Rectangle and 1 Finned Swordfish.
Another said a Finned x-wing and 2 ALS.
These are by far the most fun I have seen in a newspaper setting, I quite like it! |
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keith
Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
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| Posted: Sun Jan 11, 2009 1:42 pm Post subject: |
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The Friday puzzles are the tough ones.
Occasionally the Thusday puzzle may need an advanced move.
They are almost all posted here as "Free Press" or "LA Times / Freep".
Keith |
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