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 Trial and error 
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Posted on: Wed Sep 21, 2011 5:02 pm




Posts: 246
Location: Lisbon, Portugal
Joined: Sun Sep 18, 2011 5:40 pm
Post Trial and error
Today, 21/09/2011 I thought it was the first time I solved all the puzzles of a day, but I didn't manage to solve the difficult 7x7. I used the parity, the maximum and minimum and the habitual and nothing resulted except the very boring trial and error. Has the puzzle only subtraction special treatment and I am an ignorant or am I a lazy?

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Posted on: Thu Sep 22, 2011 2:42 am




Posts: 175
Joined: Fri May 13, 2011 2:11 am
Post Re: Trial and error
jomapil wrote:
Today, 21/09/2011 I thought it was the first time I solved all the puzzles of a day, but I didn't manage to solve the difficult 7x7. I used the parity, the maximum and minimum and the habitual and nothing resulted except the very boring trial and error. Has the puzzle only subtraction special treatment and I am an ignorant or am I a lazy?

The 7x7 subtraction only ones, when I do them, I don't even bother waiting on trial and error. It's very rare that they can be solved without them.


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Posted on: Thu Sep 22, 2011 7:47 am




Posts: 246
Location: Lisbon, Portugal
Joined: Sun Sep 18, 2011 5:40 pm
Post Re: Trial and error
No, starling, I didn't want to say the puzzle is boring for itself.

The boredom is to do many diagrams with the pencil and rubber to test each hypothesis. When I arrive at a deadlock I must return to a new hypothesis and so on. If we can inscribe all the combinations in the diagram online and with the saving explore all the hypothesis that would be different and not boring.

Regards.

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Posted on: Thu Sep 22, 2011 10:06 am




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Joined: Thu May 12, 2011 11:58 pm
Post Re: Trial and error
starling wrote:
The 7x7 subtraction only ones, when I do them, I don't even bother waiting on trial and error. It's very rare that they can be solved without them.

I'll take another look at those puzzles, and will maybe reduce the difficulty level somewhat.
Patrick


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Posted on: Fri Sep 23, 2011 12:00 am




Posts: 43
Location: Tacoma, WA, USA
Joined: Fri May 13, 2011 4:03 am
Post Re: Trial and error
Whoa! The 7 subtractions are wonderful! Don't disfigure them! Technique I find useful is to figure out where the 3 evens and 4 odds in each row/column can go, then rule out possibilities by seeing whether any of the options put too many or too few odds or evens in the next row/column, as a result of even cages having two of the same and odd cages having one of each.


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Posted on: Fri Sep 23, 2011 12:38 am




Posts: 175
Joined: Fri May 13, 2011 2:11 am
Post Re: Trial and error
jomapil wrote:
No, starling, I didn't want to say the puzzle is boring for itself.

The boredom is to do many diagrams with the pencil and rubber to test each hypothesis. When I arrive at a deadlock I must return to a new hypothesis and so on. If we can inscribe all the combinations in the diagram online and with the saving explore all the hypothesis that would be different and not boring.

Regards.

Oh, I didn't mean to imply the puzzle is boring, I actually quite enjoy guessing and testing. The way I work through the day's puzzles, though, is to do everything I can do without guess and test, and then go back and guess and test. With the 7x7 difficult, I just leave it for last because I assume I'll have to guess and test.

rossiniman, I used to do that, but didn't find it gave me sufficient information to definitively place anything all that often.


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Posted on: Fri Sep 23, 2011 9:02 am




Posts: 693
Joined: Fri May 13, 2011 6:51 pm
Post Re: Trial and error
pnm wrote:
starling wrote:
The 7x7 subtraction only ones, when I do them, I don't even bother waiting on trial and error. It's very rare that they can be solved without them.

I'll take another look at those puzzles, and will maybe reduce the difficulty level somewhat.
Patrick


Patrick, I agree with rossiniman, the beauty of this 7x7 puzzle resides in its "difficulty". Instead of decreasing it, perhaps you may introduce a new one, as I suggested in the past, an 8x8 subtractions only with reduced level of difficulty, any day of the week (a good training for the 7x7's).

The "trial and error" is absolutely necessary in "subtractions only" puzzles, combined with the definition of the parity of the individual cells, unless going to terrible equations, but any "little footstep..." is a "big step" for the final solution (this, of course, like in the rest of all difficult puzzles).


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Posted on: Fri Sep 23, 2011 9:56 am




Posts: 246
Location: Lisbon, Portugal
Joined: Sun Sep 18, 2011 5:40 pm
Post Re: Trial and error
For the first time I solved yesterday my first 12x12 puzzle (15Sep2011) and I was very proud.
But today I solved the 5x5 difficult 23Sep2011 with trial and error FROM THE BEGGINING and I was very sad! It must be so or there is a first analysis I lacked?
Why from the 8x8 and higher there isn´t more time ( a week for instance ) to present the result and to mark points? There are some days we can't apply to the games!

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Posted on: Fri Sep 23, 2011 10:40 am




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Joined: Thu May 12, 2011 11:58 pm
Post Re: Trial and error
rossiniman wrote:
Whoa! The 7 subtractions are wonderful! Don't disfigure them! Technique I find useful is to figure out where the 3 evens and 4 odds in each row/column can go, then rule out possibilities by seeing whether any of the options put too many or too few odds or evens in the next row/column, as a result of even cages having two of the same and odd cages having one of each.

I'll first try to solve that particular puzzle myself (I started, already
found that I do need the parity checks..) and see how much trial
and error is needed. If it's not too much (e.g. 2 or 3 options here and
there), then I think it'll be fine to leave things as is.

Patrick


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Posted on: Fri Sep 23, 2011 10:52 am




Posts: 2209
Joined: Thu May 12, 2011 11:58 pm
Post Re: Trial and error
jomapil wrote:
For the first time I solved yesterday my first 12x12 puzzle (15Sep2011) and I was very proud.
But today I solved the 5x5 difficult 23Sep2011 with trial and error FROM THE BEGGINING and I was very sad! It must be so or there is a first analysis I lacked?

I think the 5x5 difficult is almost always solvable with analysis
(someone correct me if I'm wrong..), simply because it's such
a small puzzle.

Patrick


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