At what point have I cheated ?

Advanced methods and approaches for solving Sudoku puzzles

At what point have I cheated ?

Postby andytheviking » Fri Jun 03, 2005 2:50 pm

Where do people believe that normal working out ends and artificial assitance begins.
With the times puzzles I have different amounts of 'workings' out that I allow myself to do dependent on the difficulty.
i.e. Easy - pen must not touch paper other than writing the answers in and I have 2 stops on my train journey to solve them.
Medium - still no 'workings' allowed but the time scale is a little longer
Difficult - I allow myself to jot possible numbers in the margins of the paper, but usually don't have to.
Fiendish - anything goes in terms of pen and paper workings - e.g. redrawing grids with possible values etc. Then I copy it to a spread sheet and print out a larger version so I can see the pairings etc more easily. If I'm still not there I use some 'utilities' I've put together on my spreadsheet to highlight certain values etc. Finally (after a few days) I look on these boards and wait for Animator to drop the appropriate hints (thanks Animator!!:D ).

What are your self imposed 'rules' ?
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Postby Guest » Fri Jun 03, 2005 4:13 pm

I think the only thing that is a bit unnecessary out of all that is the redrawing new grids part. I am a great believer in pencilmarks, and use them all the time for Difficult and Fiendish puzzles, but I avoid using them with Easy and Mild.

For me redrawing the grid goes too far because you don't actually need to - having said that I asked Animator for help last week! (Thanks) But honestly, they are all solvable by logic, so why make it too easy for yourself?

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Postby george-no1 » Fri Jun 03, 2005 4:14 pm

btw, the above post was from me, not a 'guest'

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Postby paulf2127 » Fri Jun 03, 2005 5:08 pm

I am the same pretty much. I read with interest that Wayne doesn't use pencil marks ( although he asays he might use them in his head...). I use full pencil marks for difficult and fiendish ones and then logic from there.

I have (almost) a 100% record although I think it was 143 or 148 which was a bastard. Todays fiendish (161) took me 31:25.
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Postby lunababy_moonchild » Sat Jun 04, 2005 5:55 am

I have my own self-imposed rules on solving, which includes reprinting the original in the event I go wrong. Do I consider this cheating? No. Either I do it or I don't, it's a game. Some days I'm better at it than others and I'd prefer to solve on my own. I usually do. Starting from scratch again happens only occasionally and I have always managed to solve the puzzle from this one reprint. I'm not too proud to ask for help in the event that I'm really stuck - which happened once - and I don't consider that cheating either.

This little puzzle has gripped me totally and utterly and yes, I'd like to be really, really good at it. I'm not, I'm just average, so I'll have to live with that. The point of the puzzle, imho, is entertainment so I take pleasure in the fact that I can solve the majority of the ones that I attempt and that there are ever harder ones for me to be challenged with. The challenge is the key, for me.

As for cheating, well that's a whole topic unto itself but my take is using computing technology to solve a puzzle in nanoseconds then sending it in as a bona fide competition entry would be cheating. Although I do think having the skill to write a solver is admirable.

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Postby george-no1 » Sat Jun 04, 2005 9:24 am

lunababy_moonchild wrote:I have my own self-imposed rules on solving, which includes reprinting the original in the event I go wrong. Do I consider this cheating? No. Either I do it or I don't, it's a game.

But surely you'd always rather not, whatever the circumstances? I think the actual game itself is how far you push yourself to solve it - it's only a numbers on a page if you redraw the grid or use a solver (although I agree that writing a solver is pretty impressive).

Any thoughts?

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Postby lunababy_moonchild » Sat Jun 04, 2005 1:11 pm

Yes, I'd always rather not. I'd rather prefer to be good enough to do the Very Hard puzzles from the program in a matter of 10 minutes too but that isn't going to happen.

As mentioned, I rarely reprint the puzzle and start from scratch, but I will if I'm determined enough to solve it. Does it impede my enjoyment of the game? No. Is it cheating? Actually I never really thought about it in those terms. Would I like to be more intelligent and be able to solve any puzzle put before me with a matter of ease? Oh yeah, but then I'd get bored. I'd also like to be taller but there you go!

The rules are stated and are easy to follow. Self-imposed rules are there to further challenge, personally.

It's a game. A pass-time. Entertainment. There to be enjoyed for the fun of it and, yes the challenge. However that comes, though.

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Pencil and paper, every time.

Postby Togidubunus » Sun Jun 05, 2005 1:36 pm

I use a pencil. I started out flagging up the possibles with pencil marks in the early days, but now I do all the chalking up of possibles in my head and I fill in when I'm absolutely certain, then rub out any which are wrong when they reveal themselves. When I find an anchor number I put a circle round it. If the whole puzzle goes completely tits-up, I ink in the anchors and rub out the whole thing. The newsprint does get very faded after several rubbings-out, though. I've just finished Times Fiendish no. 162 in 35 mins. It has 4 anchors, which is not very fiendish, in my view.
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Postby NigelG » Tue Jun 07, 2005 1:42 pm

I only use pencil marks on the Fiendish ones now. I didn't need them for the samurai one this weekend either.

I now time myself on the difficult ones and only do the easy/mild ones when I really want to avoid work.

They take less than 5 minutes to do, so not much scope to skive:D
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Postby Pseudo Kiwi » Wed Jun 08, 2005 5:46 am

I'm with Luna on this. Part of the attraction of the puzzles for me is that people have so many different ways of solving them. I prefer not to guess but I wouldn't call it cheating if you do end up taking a guess. It's just that some methods of solving the puzzles are more satisfying than others.

I use pencil and paper. Sometimes I rewrite the grid just so that I don't have problems with rubbing out newsprint. Similar to what Togidubunus does, I put a ring around the first ten or so "easy to get" numbers, so that I don't rub those out if everything turns to custard. If I do guess, I put a square around every number that results from the guess. I've only once resorted to a "double guess", and I used diamonds to represent that, though now I try and avoid guessing full stop.

Once I used the carpet-bombing method on excel, and no, I don't think that's cheating either, but I didn't derive a lot of satisfaction out of solving it that way.

Had a go at a couple of fiendish ones last night. The first one (June 3:?: - the one with no threes in at the start) DID turn to custard. But to my surprise I cracked the June 4:?: one in 40-odd mins. Togidubunus - I think that might be the one you mentioned, in which case you just beat me:(


Pseudo Kiwi
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Postby andytheviking » Wed Jun 08, 2005 9:45 am

Thanks for the replies, it's interesting to see that I don't seem to be too badly adrift of what 'most' other people are doing.

I like the idea of the circles and squares etc as I'd often thought how best to back track once I realise I've made a mistake (which is usually only on the fiendish ones), hence the use of the excel printouts that I can easily start over from a particular point.

My objective is to do a fiendish without ANY workings, I need a fair bit more practice before that though. Right off to study x-wings, pairings three of a kinds etc

Must get a life back, I ended up 'racing' a complete stranger, sitting next to me on the train, to complete a mild the other day. He got off before either of us finished though !!
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Is this "double guessing" / cheating?

Postby Anette » Sat Jun 11, 2005 1:54 pm

Is this cheating?

I have started out with the “Very Hard” sudoku from Times like this:


After solving according to logic so far, I ended up with the following:


Then I could see no more “simple” logic ways to solve it, so I started looking at the 2 possibilities in Column 1 and did the following:

Option A: If R1C1 = 7, then 7 can go nowhere else in Row 1. For R1C6, the only possibility is then 6

Option B: If R1C1 = 1, then R8C1 has to be 7. Then R4C8 has to be 1. Then R3C4 has to be 7. Then R1C6 cannot be 7, and the only possibility for it is 6.

So either way, R1C6 had to be 6, and from there, I could solve the puzzle.

Is it considered cheating to set up 2 alternatives like that? I did draw some rings and squares around the pencil marks, but might as well have done it in my head since the chain wasn't that long.

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Postby Anette » Sat Jun 11, 2005 1:57 pm

Sorry, meant "Then R8C4 has to be 1"

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Postby george-no1 » Sun Jun 12, 2005 12:02 pm

That's not really cheating in my opinion, because you didn't just guess blindly, you saw that either way it had to be a 6, which is a logical process (although based on trial and error). Correct me if I'm wrong anyone, but the process you carried out was probably a 'Nishio'.

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Postby Animator » Sun Jun 12, 2005 12:13 pm

It's not a Nishio.

A Nishio is trial and error limited to one single number. You have a Nishio when you find a row/column that cannot have the number you tried to fill in. If that is the case then you know that that particualar cell you tried is not that number.

This does not happen with the number 7 nor with the number 1. So it is simply Trial And Error.

The technique you are missing in your example-grid is an X-wing in the number 6.
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