How far can I expect to go?

Advanced methods and approaches for solving Sudoku puzzles

How far can I expect to go?

Postby snapdragon » Sat Aug 06, 2005 1:57 am

I try to do the puzzle every day from www.dailysudoku.com. I can usually do the mediums, but generally give up on anything harder. I have limited time, limted patience and limited brainpower. I think I have been doing a form of x wing, but am just now getting my head around the other wings and fish. (I just stumbled into this discussion yesterday).

My question: Without resorting to coloring, forcing chains, trial and errors, computer programs, should I be able to solve the harder puzzles? How long are people spending on them? After 45 minutes, I take the dog for a walk and conveniently forget about the darn thing.
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Postby Karyobin » Sat Aug 06, 2005 7:51 am

Ooohh, you're gonna hate me.

I just went to that site for the first time (inspired by your thread). There was a 'Hard' one on display and I solved it in about 6 minutes. At this point I must admit I used simes's program to put in all the pencil marks, coz I thought it'd take longer, but once they were in - hey presto! Nothing more esoteric than a naked triple is required and the whole thing falls apart, you can barely keep up with yourself.

If today's is a fair measure, then I'd recommend you just concentrate on the simple constructs, they seem to be all that's required.

Oh yeah, and if you are printing them out and doing them by hand just be aware that although the thinking is exactly the same, the time-frame required to solve them is quite different.
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Postby lunababy_moonchild » Sat Aug 06, 2005 8:09 am

I haven't solved a puzzle in months, however, when I was solving I managed to solve a Fiendish in roughly 3 days without any sophisticated solving methods at all. Can't speak for anybody else, obviously.

Without resorting to coloring, forcing chains, trial and errors, computer programs, should I be able to solve the harder puzzles?


I don't know. My impression, from what I've read on this site, is that Hard and above need the advanced techniques to solve them. Since I've never gotten that far I can't really say (I have yet to master any of the more sophisticated solving methods and am not sure that I want to). I'd like to be able to solve any puzzle that comes before me without bursting my brain learning the advanced methods but I can't, so I can either choose to learn these methods or stay in the Medium category (or not solve at all), depending on the level of entertainment I would like to derive from the puzzle. And that seems to be the key to me - level of entertainment derived from the puzzle. I'm not sure that I really want to study that hard in order to learn how to play a game.

The challenge, it seems to me, is with the self. The puzzle is a game, entertainment, a past time. If you want to get faster, then do what it takes to achieve that. If you want to learn the advanced techniques then do that. If, however, walking the dog is more attractive then that's what I'd do.

The beauty of this puzzle, as far as I can see, is that these choices are there. For me, I can advance, or not, as I choose.

Luna
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Postby snapdragon » Sat Aug 06, 2005 11:49 am

You use a program to put in the pencil marks? That DOES seem like cheating! If I can't do it with paper and pencil, then I'd rather not bother:)
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Postby Karyobin » Sun Aug 07, 2005 3:30 pm

Aaahh now, let's be clear - I've not been to that particular site before so I used the program in order to get into the puzzle quickly to get some idea of the severity.

I have/will never use a program to automatically place pencil marks in puzzles that I set myself!

By the way, I've personally found (having solved literally hundreds with paper and pencil) that placing the pencil marks with a computer (though still performing all the thinking by oneself) leaves one much more time to examine the logical structures, as one simply spends less time writing.

When you get to the really hard ones, *clicking* is much swifter than writing/erasing.
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"hard" puzzles

Postby susie » Mon Aug 08, 2005 2:31 am

Snapdragon asked about time spent on hard puzzles. Today was my first time succeeding at the hard ones. I practiced and practiced on mediums until I could reliably get them right, then trepidatiously tried a hard one and got it in about an hour and a quarter. Two more hard-ies later, I feel I have totally let my responsibilities go for the day, but have shown myself I could do a hard puzzle. Still no clue about xwings, swordfish, chains, colors, and other such techniques. For now, I'm just feeling good.
Susie
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Postby Ianac » Mon Aug 08, 2005 6:25 am

Thanks for giving me another sudoku site. Tried the "hard "puzzle which required nothing more than finding the odd naked triple. Like everything else keep the KISS ( keep it simple stupid )principle in mind. Concentrate on isolating "possibles" to a column , row or square - this seems to solve all but the very complex puzzles
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Postby Karyobin » Mon Aug 08, 2005 9:39 am

You won't need X-wings or the like until you start on the Very Hard's. Believe it or not, the only hard bit about X-wings is finding them, the principle is really easy. Look at:

http://www.angusj.com/sudoku/hints.php

and

http://www.simes.clara.co.uk/programs/sudoku.htm

for advice.
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How far can I expect to go

Postby Cec » Mon Aug 08, 2005 10:57 am

snapdragon wrote "... How long are people spending on them (puzzles)?. After about 45 minutes, I take the dog for a walk and conveniently forget about the darn thing."

Being a dog lover, I couldn't resist asking is it the puzzle you conveniently forget about or the dog!

After doing these puzzles for about two months it now seems more tedious to pencil in the candidates for hard puzzles and Karyobin's comments make sense in "placing the pencil marks with a computer" which obviously reduces writing time and hence provide more time to attempt solving the puzzle.

Regards, Bonsai Cec
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Very hard

Postby Anette » Wed Aug 10, 2005 5:45 pm

I tried the "hard" and that wasn't too bad, but now I got stuck on the "very hard" from the same website (Sunday August 7th). This is how far I've come, I can't seem to find any X-wings or naked pairs, but I know that I often have problems spotting them. Could somebody give me a hint?

8**1**47**
**57***38
6*79*845*
5*9**1***
*7**9**15
*****53*9
*521*7**4
78***9***
**68**5**
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Postby Anette » Wed Aug 10, 2005 5:46 pm

One * too much, this is how it's supposed to be

8*1**47**
**57***38
6*79*845*
5*9**1***
*7**9**15
*****53*9
*521*7**4
78***9***
**68**5**
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Postby Karyobin » Wed Aug 10, 2005 7:15 pm

You can get rid of some candidate 3's in column 2 and in row 5. This tells you where you can place a 6 in column 6.
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Postby Anette » Wed Aug 10, 2005 7:42 pm

Thanks!

Can't understand how I didn't spot that until now!
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Postby princessj89 » Fri Aug 12, 2005 11:19 pm

I have been doing the puzzles from the newspaper with pencil and a big eraser for less than a week. It takes me FOREVER to complete a puzzle! I just tried one online and it took me exactly 9 minutes 12 seconds. It didn't seem challenging at all, especially with the "How am I doing?" button. When you click the button, it highlights which number you incorrectly places on the grid. Kinda lame I think...
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Postby Karyobin » Sat Aug 13, 2005 9:42 am

Then don't click it.
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