dimpleqonx creative solution for Boolean Algebra by veky - python coding challenges

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dimpleqonx solution in Creative category for Boolean Algebra by veky

boolean=lambda x,y,o:1&~"dimpleqonx".index(o[1])>>y>>x>>y

Sept. 3, 2014

Comments:

DiZ on Sept. 4, 2014, 6:07 a.m.
Amazing! How did you find this?!

veky on Sept. 4, 2014, 6:11 a.m.
I'm a mathematician, remember? This is the stuff I eat for breakfast. ;-) If you want to be enlightened, meditate on <a href="http://en.wikipedia.org/wiki/Truth_table">http://en.wikipedia.org/wiki/Truth_table</a>#citeref-tlp5.1012-1 for a while. ;-D

DiZ on Sept. 4, 2014, 6:36 a.m.
Ooh... Now I understand better, thanks for meditation before work ;)

Sim0000 on Sept. 4, 2014, 12:06 p.m.
57 chars!!!

veky on Sept. 4, 2014, 1:31 p.m.
Yeah, so? It could have made it 56 if I wanted it short. :-))

DiZ on Sept. 4, 2014, 2:26 p.m.
Thanks to your tips, an even shorter <a href="http://www.checkio.org/mission/boolean-algebra/publications/DiZ/python-3/gnu-puns/">solution</a> (53) :D

veky on Sept. 4, 2014, 2:50 p.m.
The weird thing is, I didn't even try to golf there. I just wanted to make a cool puzzle (as in "why does this work?"). But nevertheless, I'm glad I inspired you. Your solution is truly brilliant. :-DD

pynur on Oct. 8, 2014, 4:06 p.m.
i don't understand how it's work. But i like how it's look

veky on Oct. 8, 2014, 7:44 p.m.
Have you read the comments? Especially this one: <a href="http://www.checkio.org/mission/boolean-algebra/publications/veky/python-3/dimpleqonx/">http://www.checkio.org/mission/boolean-algebra/publications/veky/python-3/dimpleqonx/</a>#comment-17831

NikhilVashisth on Oct. 20, 2014, 10 a.m.
I don't understand anything after "lambda x,y,o:" (O.o) Can you tell us what exactly happened there?

veky on Oct. 20, 2014, 11:42 a.m.
<blockquote> I don't understand anything after "lambda x,y,o:" (O.o) </blockquote> Well, at least you don't have problem with the lambda, which sets you apart from about 70% of people here. :-Q <blockquote> Can you tell us what exactly happened there? </blockquote> Of course, but first, have you read the other comments? Especially the one with the link to Wikipedia?

NikhilVashisth on Oct. 20, 2014, 7:01 p.m.
Yeah, I understood the truth table and all the operations. Am I still missing something? If not, what does the {1&~"dimpleqonx".index(o[1])>>y>>x>>y} do?

veky on Oct. 20, 2014, 11:29 p.m.
It converts o (by its second letter, which is different for every operation) into a number 0~15 (in fact I invert the number since the numbers in the upper range are more useful), and then extracts the bit of that number corresponding to the combination of x and y given. For example: x=0, y=1, o="implication". Then o[1] is 'm', "dimpleqonx".index of it is 2, its invert is -3= binary ...1111101 (its last 4 bits are 1101, which is a truth-value column for implication). Of that, I extract (2y+x)th bit from the right counting from 0, which in this context is the value of fours, that is, 1. It is accomplished by shifting that value 2y+x bits to the right, and then extracting last bit with 1&. Anything else needs explaining?

petrch on Dec. 1, 2014, 12:36 a.m.
I love this one.

veky on Dec. 1, 2014, 6:44 a.m.
Thanks. Be sure to check out other solutions I wrote as you progress here, you'll probably like them. ;-)

petrch on Dec. 1, 2014, 9:36 a.m.
This was exactly my intention :). This kind of solutions makes the time on checkio worth it.

sirmax on Jan. 23, 2015, 1:43 p.m.
Than you for explanation. I almost got it by myself, but decided to look through the comment. Beautiful and smart solution.

veky on Jan. 24, 2015, 9:22 a.m.
An idea for admins: a "spoiler" feature? So people aren't too tempted to just look at the comments. :-D

OMFGNuts on Jan. 26, 2015, 9:21 a.m.
User can 'adblock' parts of webpage :D

veky on Jan. 26, 2015, 9:38 a.m.
Ah, you and your innovative solutions. :-D

bryukh on Jan. 26, 2015, 11:01 a.m.
[spoiler]Yeah, spoiler feature work in comments

bryukh on Jan. 26, 2015, 11:02 a.m.
Oh! I found a bug. He he. Nice :-)

veky on Jan. 26, 2015, 3:01 p.m.
Witchcraft! :-P

HappyBros on Dec. 5, 2014, 12:24 p.m.
Oookay... Nice one!

veky on Dec. 6, 2014, 8:04 a.m.
Thanks. Wait until you see others. ;-]

mandalorx on Feb. 21, 2015, 3:02 p.m.
Oh I like this!!!

veky on Feb. 21, 2015, 6:54 p.m.
Read other solutions of mine here, I think you'll find a lot to like. ;-)

kryksyh on April 9, 2015, 6:50 p.m.
O.M.G. I don't know what it is, but I like it!

veky on April 9, 2015, 7:13 p.m.
I have a feeling you'll like other solutions of mine, too. ;-) Well, do you want to know what it is? If yes, that can be arranged. :-) First, you can read the comments above. Then, if there's anything else you'd like to know, just ask.

kryksyh on April 9, 2015, 7:50 p.m.
/* there was wrong comment */ Yep, already get it, simply brilliant!

veky on April 9, 2015, 7:52 p.m.
Hmm... is this a comment to this solution, or another one ("`What's up, doc?`")? If the latter, then yes, that's correct. :-)

kryksyh on April 9, 2015, 7:57 p.m.
Yes,I was all into that one, so overlooked what I answer to. Both are just awesome!

waxdesf on May 21, 2015, 2:23 p.m.
This is scary.

veky on May 21, 2015, 3:04 p.m.
I agree, but the Scary category has been discontinued. :-D

fuzzy-focus on Aug. 12, 2015, 5:51 p.m.
Holy crap. That is almost reminiscent of Perl. I needed quite some time to understand that. I like it.

veky on Aug. 12, 2015, 7:50 p.m.
You should have seen my Perl, while I was a fan of it. :-D

fuzzy-focus on Aug. 13, 2015, 11:15 a.m.
Seriously though, when you sat down to write this one it was with a definite "let's scare the noobs, shall we?" attitude, right? How long did figuring out how to write this function take you?

veky on Aug. 13, 2015, 12:20 p.m.
Why do people always think I want to scare the noobs? [While noobs themselves only rarely think so.] I want to teach them, that's not the same - although it has some common elements. :-) But here, even that wasn't a factor. I wasn't thinking of noobs at all (see "What's up, __doc__?" for a learning experience:). I just thought how words are so clumsy a way to specify boolean operations, and how indices into a <a href="http://i.stack.imgur.com/X1w0b.png">boolean function table</a> would be much nicer, since then I'd just extract the required bit. That made me think about what would a nice injection from that set of words to range(16) be, and I realized they all have different second letter. From there, the solution was mostly obvious. :-) Seriously, it took maybe half a day. But notice that I knew the theory of Boolean functions before. ;-) And when people saw what's possible, they made much awesomer solutions: see GNU puns, for example, and also the comments there. ;-)

fuzzy-focus on Aug. 13, 2015, 1:30 p.m.
Yeah the “What’s up, doc?” solution was nice. And I get how that one had sort of a teaching intention :) This one seems a little intentionally cryptic though :) But yeah, I get what you are saying. And as I said, I quite enjoyed it ;) Now I gotta take a look at those GNU puns.

anonymorf on Sept. 1, 2015, 2:59 p.m.
This is awesome :D

veky on Sept. 1, 2015, 6:06 p.m.
Thanks. :)

totee19 on Oct. 22, 2015, 12:02 a.m.
Great solution!!! Incredible

veky on Oct. 22, 2015, 12:20 a.m.
Thanks. :-) Be sure to see Gnu puns, too. ;-)

M157q on Nov. 5, 2015, 11:33 a.m.
bravo! the beauty of math! o_o

notsinglephoton on Nov. 15, 2015, 3:41 p.m.
Do I understand correct, that in part: "dimpleqonx".index(o[1]) you take second letter of 'o' (for example 'x' in 'exclusive') and get index where this letter is in the word 'dimpleqonx' (for this case 9)? But I still do not know what is going on in 1&~ and <blockquote> <blockquote> y>>x>>y </blockquote> </blockquote> Can you explain step by step what is happening here and what is the priority of the operations? How do you construct such phrases?

veky on Nov. 15, 2015, 3:59 p.m.
Yes, you're right about the first part. That way, I map the operations to indices in the <a href="https://en.wikipedia.org/wiki/Truth_table#cite_ref-tlp5.101_4-0">truth-value table</a>. In fact, the upper values are more interesting, so I invert (`~`) the output. Now that I have a binary number (nybble) whose 4 bits encode the truth result for each combination of inputs, I just need to extract the (yx)th bit from it. That's standardly done by shifting it the appropriate number of bits to the right (with `>>`), and then extracting the last bit (with `1&`). The only remaining question is, what is the appropriate number of bits? If x and y are 0, I need the last bit (no shift needed). If x is 1 but y is 0, I need next-to-last one, so I have to shift 1 position. And so on... it's easily seen that the index of bit to be extracted (from the right) is exactly a 2-bit number yx, that is, y*2+x*1 = 2y+x. And to shift something 2y+x positions, is the same as shift it by y, then by x, then again by y positions. And that's what I've done above. All clear? :-)

notsinglephoton on Nov. 15, 2015, 4:22 p.m.
Yes, much better, thank you. I didn't know about this '1&', something new to me, also I need to practice bitwise operations in python. Encoding solution in "dimpleqonx" is quite clever. I guess you are security specialist or one of those guys I meet at university, who are top5 in every math/logic game in Europe, or both, am I right? :) Thanks again, have a nice day.

veky on Nov. 15, 2015, 10:37 p.m.
1& is also a bitwise operation. 1&x is a bitwise AND of 1 and x. And it gives the last bit of x (just as x%2 does). No, I'm not a security specialist [bitwise operations are not only for security... it's as if you see someone very good with arithmetic, and say they must be an accountant:], but I have a PhD in mathematical logic (I guess it shows:). And (about that top5) I'm not very competitive in fact - though I like teaching people, and have a bit unusual method, so people often get the wrong impression. :-)

Vooja on May 15, 2016, 7:23 p.m.
It's magic. I don't understand this.

veky on May 17, 2016, 6:31 a.m.
Do you want to understand? :-) And have you read the comments?

Czarinov on Aug. 10, 2016, 3:37 p.m.
That's pretty awesome...

veky on Aug. 10, 2016, 5:10 p.m.
I assume you've already seen the GNU puns? :-)

Czarinov on Aug. 10, 2016, 6 p.m.
No, I haven't. I meant what I said and that's your solution was awesome :D. I've just learnt that GNU is an OS.

veky on Aug. 11, 2016, 4:24 a.m.
I meant <a href="https://checkio.org/mission/boolean-algebra/publications/DiZ/python-3/gnu-puns/?ordering=most_voted">this</a>. It was inspired by this solution, and it's much better. See the comments, too. :-)

przemyslaw.daniel on July 21, 2017, 6:20 a.m.
This is brilliant idea. Surprisingly this can be even shorter when ord function is used

veky on July 21, 2017, 2:06 p.m.
It can be done shorter in a myriad of ways. See <a href="https://py.checkio.org/mission/boolean-algebra/publications/DiZ/python-3/gnu-puns/">GNU puns</a> (and comments). ;-)

Layort on Feb. 19, 2022, 2:08 p.m.
excellent! I'need some time to digest it. :-)

veky on Feb. 19, 2022, 2:08 p.m.
Take all the time you need. When you give up, read the comments. ;-)

Klimchick on March 10, 2022, 4:22 a.m.
veky as usuall...)))

veky on March 10, 2022, 6:48 a.m.
Double comment as not very usual here. :-]

Klimchick on March 10, 2022, 7:32 a.m.
不不不不 I mean, your solut as usual is awesome)))

Look up in the Dict()

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