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keith
Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
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 Posted: Sat Oct 22, 2011 1:25 am Post subject: Hard puzzles: A new source? |
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These have been showing up in the Detroit Free Press as "Universal Sudoku Puzzle", part of an ad for a hearing aid place. My challenge is to do them on paper without pencil marks.
I anyone likes this one, I can post more.
| Code: | Puzzle: AD111021
+-------+-------+-------+
| . 5 . | 1 7 . | . 4 . |
| 8 . . | . . 5 | 9 . 2 |
| 2 . . | . . . | . . . |
+-------+-------+-------+
| . . 1 | 9 . . | . 6 . |
| . . . | . . . | . . . |
| . 7 . | . . 6 | 4 . . |
+-------+-------+-------+
| . . . | . . . | . . 5 |
| 1 . 3 | 6 . . | . . 9 |
| . 2 . | . 9 7 | . 3 . |
+-------+-------+-------+ |
Keith |
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Sat Oct 22, 2011 4:32 am Post subject: |
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| I never noticed your comment about pencil marks. I used them and it was basics only. |
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Pat
Joined: 23 Feb 2010
Posts: 207
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| Posted: Sun Oct 23, 2011 9:34 am Post subject: |
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thanks
it's a 1-move puzzle
-- the interesting thing is, it has 2 different solution-paths:
- c3 "hidden" duo {2,8}
- (4) c1\b4
this is my chance to ask,
since the puzzle can be solved without the duo, does it qualify as Hard ? |
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Sun Oct 23, 2011 3:55 pm Post subject: |
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| Quote: | this is my chance to ask,
since the puzzle can be solved without the duo, does it qualify as Hard ? |
I interpret this not to be Hard in the abstract, but equivalent to puzzles on this site with the Hard rating, that do not require advanced moves. |
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Pat
Joined: 23 Feb 2010
Posts: 207
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| Posted: Mon Oct 24, 2011 12:02 pm Post subject: |
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| keith wrote: | | My challenge is to do them on paper without pencil marks. |
the textbook example of not using "pencilmarks"
comes from gsf (2007.Jan.17) --
74.3.9.51.2.....8.5...2...32..6.3..7.........1..2.5..66...3...2.3.....7.95.1.7.38
| Code: |
7 4 . | 3 . 9 | . 5 1
. 2 . | . . . | . 8 .
5 . . | . 2 . | . . 3
-------+-------+------
2 . . | 6 . 3 | . . 7
. . . | . . . | . . .
1 . . | 2 . 5 | . . 6
-------+-------+------
6 . . | . 3 . | . . 2
. 3 . | . . . | . 7 .
9 5 . | 1 . 7 | . 3 8
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-- is this considered Medium ? or Hard ?? |
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arkietech
Joined: 31 Jul 2008
Posts: 1834
Location: Northwest Arkansas USA
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| Posted: Mon Oct 24, 2011 1:32 pm Post subject: |
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| Pat wrote: | | -- is this considered Medium ? or Hard ?? |
Since it has no sets required to solve it I would call it an Easy. |
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Pat
Joined: 23 Feb 2010
Posts: 207
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| Posted: Mon Oct 24, 2011 1:34 pm Post subject: |
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| arkietech wrote: | | Pat wrote: | | -- is this considered Medium ? or Hard ?? |
Since it has no sets required to solve it I would call it an Easy. |
well Ruud would agree,
he has suggested that box-to-line is as easy as "hidden singles" | Ruud (2006.May.27) wrote: | When I solve with pen and paper,
I can mentally focus on each digit and---
solve locked pairs [ = box-to-line ] and hidden singles in one sweep |
so i still don't know what Medium means here---
Last edited by Pat on Mon Oct 24, 2011 2:35 pm; edited 1 time in total |
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arkietech
Joined: 31 Jul 2008
Posts: 1834
Location: Northwest Arkansas USA
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| Posted: Mon Oct 24, 2011 2:11 pm Post subject: |
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| Pat wrote: | | so i still don't know what Medium means here--- |
Medium to me requires a pair or pairs but not triples or higher to solve the puzzle. |
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Pat
Joined: 23 Feb 2010
Posts: 207
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| Posted: Mon Oct 24, 2011 3:30 pm Post subject: |
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| arkietech wrote: | Medium to me requires a pair or pairs
but not triples or higher |
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arkietech
Joined: 31 Jul 2008
Posts: 1834
Location: Northwest Arkansas USA
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| Posted: Mon Oct 24, 2011 4:01 pm Post subject: |
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| Pat wrote: | like these ?
[/list] |
Yes on the first. The second has at least a triple and I would classify it as a Hard. |
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arkietech
Joined: 31 Jul 2008
Posts: 1834
Location: Northwest Arkansas USA
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| Posted: Mon Oct 24, 2011 8:37 pm Post subject: |
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| Code: | *-----------*
|1..|...|2..|
|...|3..|.4.|
|...|.2.|5.6|
|---+---+---|
|.3.|4..|...|
|5..|.7.|1..|
|..6|..3|.8.|
|---+---+---|
|..4|2..|...|
|.8.|..6|...|
|7..|.1.|..2|
*-----------*
*--------------------------------------------------------------------*
| 1 56 3578 | 569 4 589 | 2 379 3789 |
| 68 2 578 | 3 5689 1589 | 789 4 1789 |
| 4 9 38 | 7 2 18 | 5 13 6 |
|----------------------+----------------------+----------------------|
| 89 3 1 | 4 5689 2589 | 679 25679 579 |
| 5 4 89 | 69 7 289 | 1 2369 39 |
| 2 7 6 | 1 59 3 | 49 8 459 |
|----------------------+----------------------+----------------------|
| 369 1 4 | 2 359 7 | 689 569 589 |
|*39 8 2 |*59 *359 6 | 479 1579 14579 |
| 7 56 59 | 8 1 4 | 3 69 2 |
*--------------------------------------------------------------------*
What is the next move? other than a triple? (359) is one |
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keith
Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
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| Posted: Mon Oct 24, 2011 9:49 pm Post subject: |
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I ran a few of this site's puzzle through Sudoku Susser:
EASY: Naked singles only.
MEDIUM: Hidden (pinned) singles, box-line intersections.
HARD: Naked or hidden sets.
I did find a medium that had naked singles only.
October 19 looks to be a pretty good "hard".
Keith |
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keith
Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
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| Posted: Tue Oct 25, 2011 12:33 am Post subject: |
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| arkietech wrote: | | Code: | *-----------*
|1..|...|2..|
|...|3..|.4.|
|...|.2.|5.6|
|---+---+---|
|.3.|4..|...|
|5..|.7.|1..|
|..6|..3|.8.|
|---+---+---|
|..4|2..|...|
|.8.|..6|...|
|7..|.1.|..2|
*-----------*
*--------------------------------------------------------------------*
| 1 56 3578 | 569 4 589 | 2 379 3789 |
| 68 2 578 | 3 5689 1589 | 789 4 1789 |
| 4 9 38 | 7 2 18 | 5 13 6 |
|----------------------+----------------------+----------------------|
| 89 3 1 | 4 5689 2589 | 679 25679 579 |
| 5 4 89 | 69 7 289 | 1 2369 39 |
| 2 7 6 | 1 59 3 | 49 8 459 |
|----------------------+----------------------+----------------------|
| 369 1 4 | 2 359 7 | 689 569 589 |
|*39 8 2 |*59 *359 6 | 479 1579 14579 |
| 7 56 59 | 8 1 4 | 3 69 2 |
*--------------------------------------------------------------------*
What is the next move? other than a triple? (359) is one |
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Hidden pair 68 in C5?
Keith |
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Tue Oct 25, 2011 1:18 am Post subject: |
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| keith wrote: | | arkietech wrote: | | Code: | *-----------*
|1..|...|2..|
|...|3..|.4.|
|...|.2.|5.6|
|---+---+---|
|.3.|4..|...|
|5..|.7.|1..|
|..6|..3|.8.|
|---+---+---|
|..4|2..|...|
|.8.|..6|...|
|7..|.1.|..2|
*-----------*
*--------------------------------------------------------------------*
| 1 56 3578 | 569 4 589 | 2 379 3789 |
| 68 2 578 | 3 5689 1589 | 789 4 1789 |
| 4 9 38 | 7 2 18 | 5 13 6 |
|----------------------+----------------------+----------------------|
| 89 3 1 | 4 5689 2589 | 679 25679 579 |
| 5 4 89 | 69 7 289 | 1 2369 39 |
| 2 7 6 | 1 59 3 | 49 8 459 |
|----------------------+----------------------+----------------------|
| 369 1 4 | 2 359 7 | 689 569 589 |
|*39 8 2 |*59 *359 6 | 479 1579 14579 |
| 7 56 59 | 8 1 4 | 3 69 2 |
*--------------------------------------------------------------------*
What is the next move? other than a triple? (359) is one |
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Hidden pair 68 in C5?
Keith |
Unless I'm missing the point here, that's not an answer to Dan's question since your 68 HP is the complement to Dan's 359 triple. |
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keith
Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
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| Posted: Tue Oct 25, 2011 5:17 am Post subject: |
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I thought Dan was pointing out the triple in R8, not in C5.
If you want to exclude the triples in R8 and C5, there is an X-wing 8 in R35, and another in C15.
Keith |
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Pat
Joined: 23 Feb 2010
Posts: 207
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| Posted: Tue Oct 25, 2011 11:03 am Post subject: |
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| keith wrote: | | Hidden pair {6,8} in c5 |
yes
my NQS post is meant to illustrate the trickiest puzzles at that level
( box\line, line\box, "hidden" duo, "naked" duo ),
and that's why i included joel64's puzzle ( 126 # 110 ) |
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Pat
Joined: 23 Feb 2010
Posts: 207
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| Posted: Tue Oct 25, 2011 11:30 am Post subject: |
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| keith wrote: | October 19 looks to be a pretty good Hard
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sorry i don't see the puzzle,
could you post it ?
sounds like the level of puzzle i'd enjoy
i got the impression that the
experts on this forum
only care for extra-tough puzzles
needing "forcing chains" or "forcing nets";
are there any like me,
who'd enjoy a tricky puzzle
even if it is only Medium or Hard ? |
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keith
Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
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| Posted: Tue Oct 25, 2011 1:15 pm Post subject: |
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Pat, go here:
http://www.dailysudoku.com/sudoku/index.shtml
Click on "SuDoku Archive", then select any "Hard" from the "Classic" column.
| Code: | Daily Sudoku: Wed 19-Oct-2011 Hard
+-------+-------+-------+
| 9 1 . | 3 4 . | . . . |
| . . 5 | 8 . . | 3 . . |
| . . . | 7 . . | . 4 . |
+-------+-------+-------+
| 2 . . | . 8 . | . . . |
| 7 . 6 | . . . | 5 . 4 |
| . . . | . 9 . | . . 8 |
+-------+-------+-------+
| . 9 . | . . 8 | . . . |
| . . 8 | . . 3 | 1 . . |
| . . . | . 7 1 | . 8 2 |
+-------+-------+-------+
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Play this puzzle online at the Daily Sudoku site
Keith |
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arkietech
Joined: 31 Jul 2008
Posts: 1834
Location: Northwest Arkansas USA
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| Posted: Tue Oct 25, 2011 2:00 pm Post subject: |
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| keith wrote: | I thought Dan was pointing out the triple in R8, not in C5.
If you want to exclude the triples in R8 and C5, there is an X-wing 8 in R35, and another in C15. |
I was just strying to show the puzzle was more than a Medium.  |
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Pat
Joined: 23 Feb 2010
Posts: 207
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| Posted: Wed Oct 26, 2011 12:59 pm Post subject: re: 2011.Oct.19 Hard |
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| keith wrote: | Daily Sudoku: Wed 19-Oct-2011 Hard
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thanks, yes, that i can find -- sorry, where you had earlier said | Quote: | | I ran a few of this site's puzzles---October 19 looks to be a pretty good "hard" |
i took it to refer to your opening post ( Detroit Free Press ).
as for the 2011.Oct.19 Hard -- again i'm confused,
why is this called Hard ?
solved with 1 move, b7 "hidden" duo {2,7} -- triple not needed
Last edited by Pat on Wed Oct 26, 2011 2:06 pm; edited 1 time in total |
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