bearophile Wrote:

> Chris Miller:
> 
> >> putr( map((int el){ return format("%2d", el);}, row).join("  ") );
> >So does any of that have a practical application for D?
> 
> 1) This is a D forum, and lot of people here like various languages. I like many languages. I don't think adding few extra lines in my post may hurt.
> 2) D is an evolving language, and new things may be added to it in the future. If you don't discuss things you only keep C/C++ as a reference, and you may end with a C++-like-only language.
> 3) I think functional programming will become more important in the future. The last version (the one starting with putr) is actual D code you can run with my D libs. It's hairy, so it shows why a better syntax is very useful for that kind of programming. AST macros may help there. There is an alternative syntax you can use, plus the map of std.algorithms of D 2.x, and the tools by downs, etc.

I just wanted to know if any of those would actually work in D.  My nasty method isn't the best by any stretch of the imagination, and aside from boning back up on regular expressions I couldn't think of a better solution.

If there's a better solution, that is awesome.  I didn't recognize anything as D, and I didn't know if the last line was for D (whether for a library I do know/have or not).

> >I just didn't feel like writing a shell sort by insertion (which I have found to be the fastest for this particular data set) just then.<
> 
> Probably there are other ways to improve that (a priority queue? Fibonacci Heaps? etc), but fastSort is already written...

Perhaps.  I liked the shell sort by data exchange because it was an in-place sort, which makes it safer for larger data sets.

> >I agree that the Perl version is more readable.  I just needed something in D, since I don't know Perl, nor do I have a Perl interpreter handy.  My D version also can handle variable sized boards, which the Perl version cannot.<
> 
> I think a better-looking (and higher-level) D version can be written.

I don't disagree.  I just wanted something that worked, since having lots of tables of numbers on the site was really bland.  The images look a lot better, and help illustrate things far more effectively.

One of the things I'd like to do to the SVG maker is to change the worker function that actually makes a string that describes an SVG is to modify it to accept an array of locations as an array of locations (the struct).  That would remove the necessity of re-parsing the text to make the circle and the ending arrow.  I added the circle and arrow last, so I wasn't really thinking all the way through.  It does beg another iteration.

The original parser could also use another do-over.  It just feels a bit too fault-prone.  I haven't stress-tested it with malformed input to see how it will react, and it could certainly be a lot better.

Specifically I was in want of a C-like scanf function for the board header.

scanf("found solution for %d %d in %d steps\n", x, y, steps);

It would have been much better.  I was attempting to avoid the use of tango.stdc libraries in the spirit of SafeD.  For the life of me I couldn't find a simple exit() function, so I was forced to import stdlib.  I'm still not sure if Tango has one, though honestly I haven't continued my search.

> >I did not feel like learning enough Perl to make it handle variable sized boards, either.<
> 
> I see, then you can translate that Perl code to Python instead to D ;-)

Yeah, but the D version was more fun to write.  In addition, I'm not familiar with Python, and I'd have to make a significant investment in time to locate reliable documentation and to get myself up to speed with a working understanding of how to make things tick in Python.  Not an option, given that I'm under a lot of workload in school right now.  I was sick and missed three days.  It feels like I missed most of the quarter though.

Here is a fairly good statement of the problem .I remember now looking at it twenty odd years ago

http://www.tri.org.au/knighttour.html

Good stuff Chris

I got one to run at least and found the original problem. I followed your advice and the first time I got 2 .svg files . The first of which worked and looked good . The second gave me an array out of bounds error.

I'll have a closer look in a few hours as I have to go out but I'll chuck it in here anyway in case you spot it immediately. This was the second try which ave out of bonds on the first.result.

[tytower@localhost mystuffExperimental]$ Miller
found solution 0 0 in 135 steps
||0||33||44||17||46||31||12||15||
||43||18||61||32||13||16||47||30||
||34||1||52||45||60||63||14||11||
||19||42||59||62||51||54||29||48||
||2||35||56||53||58||49||10||25||
||41||20||39||50||55||26||7||28||
||36||3||22||57||38||5||24||9||
||21||40||37||4||23||8||27||6||


found solution 0 1 in 119 steps ||31||0||17||56||33||46||15||12|| ||18||59||32||47||16||13||34||45|| ||1||30||55||60||57||48||11||14|| ||54||19||58||49||52||61||44||35|| ||29||2||53||62||43||50||25||10|| ||20||5||42||51||26||63||36||39|| ||3||28||7||22||41||38||9||24|| ||6||21||4||27||8||23||40||37||


found solution 0 2 in 430 steps ||44||31||0||15||46||29||10||13|| ||1||16||45||30||11||14||47||28|| ||32||43||54||59||52||63||12||9|| ||17||2||51||62||55||58||27||48|| ||42||33||56||53||60||49||8||23|| ||3||18||61||50||57||24||37||26|| ||34||41||20||5||36||39||22||7|| ||19||4||35||40||21||6||25||38||


found solution 0 3 in 1849 steps ||29||32||15||0||55||34||13||10|| ||16||1||30||33||14||11||56||35|| ||31||28||61||58||49||54||9||12|| ||2||17||50||53||60||57||36||47|| ||27||42||59||62||51||48||23||8|| ||18||3||52||43||24||63||46||37|| ||41||26||5||20||39||44||7||22|| ||4||19||40||25||6||21||38||45||


found solution 0 4 in 1849 steps ||10||13||34||55||0||15||32||29|| ||35||56||11||14||33||30||1||16|| ||12||9||54||49||58||61||28||31|| ||47||36||57||60||53||50||17||2|| ||8||23||48||51||62||59||42||27|| ||37||46||63||24||43||52||3||18|| ||22||7||44||39||20||5||26||41|| ||45||38||21||6||25||40||19||4||


found solution 0 5 in 230 steps ||13||10||29||46||15||0||31||44|| ||28||47||14||11||30||45||16||1|| ||9||12||63||52||59||54||43||32|| ||48||27||58||55||62||51||2||17|| ||23||8||49||60||53||56||33||42|| ||26||37||24||57||50||61||18||3|| ||7||22||39||36||5||20||41||34|| ||38||25||6||21||40||35||4||19||


found solution 0 6 in 113 steps ||12||15||46||33||54||17||0||31|| ||45||34||13||16||47||32||53||18|| ||14||11||48||55||62||59||30||1|| ||35||44||63||58||49||52||19||60|| ||10||25||50||43||56||61||2||29|| ||39||36||57||26||51||42||5||20|| ||24||9||38||41||22||7||28||3|| ||37||40||23||8||27||4||21||6||


found solution 0 7 in 133 steps ||15||12||31||46||17||44||33||0|| ||30||47||16||13||32||53||18||43|| ||11||14||55||52||45||62||1||34|| ||48||29||60||63||54||51||42||19|| ||25||10||49||56||61||58||35||2|| ||28||7||26||59||50||39||20||41|| ||9||24||5||38||57||22||3||36|| ||6||27||8||23||4||37||40||21||


[1]+  Stopped                 Miller
[tytower@localhost mystuffExperimental]$ SVGMaker f -fileresults.txt
0 : SVGMaker
1 : f
2 : -fileresults.txt
file=results.txt
board size 0 x 0 y 0 maxx 0 maxy 0
tango.core.Exception.ArrayBoundsException@knightstour.SVGMaker(183): Array index out of bounds
[tytower@localhost mystuffExperimental]$ SVGMaker f -fileresults.txt
0 : SVGMaker
1 : f
2 : -fileresults.txt
file=results.txt
board size 0 x 0 y 0 maxx 0 maxy 0
tango.core.Exception.ArrayBoundsException@knightstour.SVGMaker(183): Array index out of bounds
[tytower@localhost mystuffExperimental]$

Here is the first and second .svg files I got.

Chris Miller wrote:
> Hmm...  Excellent point.  I'll have to rethink my submission
> mechanism.  I was going to give an email address, though sadly
> whenever I put it on the 'net in one more location, that invariably
> creates more spam for me.

On a web site you could put the mail address simply in a picture.

And another idea: many big sites have these distorted text string pictures you have to type in, sort of like a password to prove that you're human. Now, most of these are entirely random, computer generated, and whatever else fancy.

On a small-volume low profile site (no disrespect intended here), making these could be just as simple as writing, say 20 random strings in your own handwriting (maybe quickly and sloppily) on a piece of dirty paper, digitizing them, and then showing one of them at random to the user.

---

Never pay for a lock stronger than the door. -- Anon.

Georg Wrede wrote:
> Chris Miller wrote:
> 
>> Hmm...  Excellent point.  I'll have to rethink my submission
>> mechanism.  I was going to give an email address, though sadly
>> whenever I put it on the 'net in one more location, that invariably
>> creates more spam for me.
> 
> 
> On a web site you could put the mail address simply in a picture.
> 
> And another idea: many big sites have these distorted text string pictures you have to type in, sort of like a password to prove that you're human. Now, most of these are entirely random, computer generated, and whatever else fancy.

http://www.captcha.net/

> 
> Never pay for a lock stronger than the door. -- Anon.

Never pay for a door stronger than the wall next to it.

Tower Ty wrote:
> Here is a fairly good statement of the problem .I remember now
> looking at it twenty odd years ago
> 
> http://www.tri.org.au/knighttour.html

While reading your link, I stumbled on the Sequence database. A good
introduction is here:

http://www.research.att.com/~njas/sequences/demo2.html

(Excluding cheating at homework or on-line IQ tests,) this intro page is something I would have liked to read already when I was at school.

BCS wrote:
> Georg Wrede wrote:
> 
>> Chris Miller wrote:
>>
>>> Hmm...  Excellent point.  I'll have to rethink my submission
>>> mechanism.  I was going to give an email address, though sadly
>>> whenever I put it on the 'net in one more location, that invariably
>>> creates more spam for me.
>>
>> On a web site you could put the mail address simply in a picture.
>>
>> And another idea: many big sites have these distorted text string pictures you have to type in, sort of like a password to prove that you're human. Now, most of these are entirely random, computer generated, and whatever else fancy.
> 
> http://www.captcha.net/
> 
>> Never pay for a lock stronger than the door. -- Anon.
> 
> Never pay for a door stronger than the wall next to it.

Ah, captcha is free. The better!

Never pay for a door if you can get it for free. -- Ibid.