Trolling homework questions - sorting

http://codegolf.stackexchange.com/questions/16226/trolling-homework-questions-sorting

by DanBC • 13 years ago

110 49 13 years ago

codegolf.stackexchange.com

This is brilliant because it encourages thinking a little differently to come up with the wrong answer (which helps you learn to identify wrong code). Nice work OP

zhemao• 13 years ago

Well, a lot of them aren't wrong answers, just really inefficient or overly-complicated implementations.

mjcohen• 13 years ago

1. Generate all permutations of the input. 2. Return the permutation that is in order. 3. Profit!

shawabawa3• 13 years ago

  1. Output all permutations of the input
  2. There is no step 2.

You've technically outputted the input list in order...somewhere

lstamour• 13 years ago

Ooh, that's the best answer I've seen yet. Perfect!

DanBC2• 13 years ago

I love this answer and it's probably worth creating an account for you to post it.

yeukhon3• 13 years ago

The ultimate answer is to ask your young siblings to sort them for you. The price is a little time and some candy. Or since so many people are unemployed, ask them to crowdsource and work for something in return!

Or just ask wolframalpha.

HeyImAlex• 13 years ago

Set up a job through the Amazon mechanical Turk API and that might actually be possible to do programmatically.

cromulent• 13 years ago

That was my first thought - use a call to the MT api to get the sort done, and then "wait for response". Meets the requirements of the competition perfectly.

knieveltech• 13 years ago

"trollsort.c:43:3: warning: incompatible implicit declaration of built-in function ‘printf’"

Epic. Epic I say.

aembke• 13 years ago

Wow.

http://codegolf.stackexchange.com/a/16274

yeukhon3• 13 years ago

Not as impressive as this http://www.jsfuck.com/

ultimatedelman2• 13 years ago

yeah, that's why i don't code in perl

NegativeK• 13 years ago

Claiming that Perl is a bad language because you can obfuscate it just means that you've never looked for "obfuscated <better language>".

SwellJoe• 13 years ago

And, it's one of many reasons I do.

Moto74512• 13 years ago

Your everyday Perl is much nicer:

perl -e 'my $vals = ".003, .002, .005"; my @sorted = sort { $a > $b } map { $_ =~ s/ +//g; $_ } split(",",$vals); print "$_ " foreach @sorted;'

You can alias the topic variable ($_) if you're not a fan.

jeremymcanally• 13 years ago

No one suggested sleep sort? That's the ultimate trolling-but-almost-legitimate sorting algorithm. :)

mihai_ionic2• 13 years ago

And it even has the best time bound you can get for a comparison based sort. Most OS schedulers would use a heap/priority queue internally for timers, which makes sleep sort O(n log n).

gizmo686• 13 years ago

wouldn't sleep sort be O(k), where k is the largest element to be sorted? (Assuming the clock and scheduler are precise enough to achieve the correct answer the first attempt).

Moto74512• 13 years ago

I noticed this myself and decided to write a glorious example in Objective C:

http://codegolf.stackexchange.com/a/16390/11612

justinhj• 13 years ago

I wrote a version in Go http://codegolf.stackexchange.com/a/16468/11452

pedramnegahdar• 13 years ago

I just found my new favorite sorting algorithm.

Gwen_Bell• 13 years ago

This reminds me of learning Git. It was hard. Probably the hardest thing I've ever learned. But it was worth it, because I Did The Work, and now I'm a hacker.

codezero4• 13 years ago

Trolling people looking for easy answers is pointless. Folks like this won't use a single source to send in their work. The problem with this approach is you often penalize people who are truly curious and not trolls.

If you were to allow the masses to determine whether a question is a troll question or not, using an OR, allowing anyone to flip the bit, then almost every question would be considered a troll question. You get a lot of false positives.

Providing a thorough, quality answer to a troll question won't help advance that troll's career, they will pay the price later, for sure, when their intellect is on the line.

Providing a trolly answer, and treating the question asker as insincere will inevitably treat a sincere person like shit, and turn them off entirely from entire genres and disciplines.

Treat resources as sincere, and those who wish to abuse them for temporary short term gain will, and I am very confident about this, end up fucking themselves over.

*If you downvote this, please let me know what you disagree with, I'm open to debate.

yeukhon3• 13 years ago

I didn't downvote you. Two thoughts:

1. I read the whole thing three times and I still don't really understand what your objective is.... and do you actually know the purpose of the trolling thread or not. The purpose is to have fun and pretend one as a student who is under some stress and is trying to figure out some funny yet creative ways to brain fuck with the TA or professor. Even if it receives F, whatever.

Treat resources as sincere, and those who wish to abuse them for temporary short term gain will, and I am very confident about this, end up fucking themselves over.

Well, most of the questions we ask on the Internet are really for short-term gain anyway. We hope someone could tell us why the fuck the X.so file is not linked and we move on afterward.

Most of the answers are actually not some quick jerky answers. people actually took time to write them. And in the process of writing an answer, the author learns. Ever heard of "one teaches, two learns?"

2. Why so serious? The Internet is full of shit half of the time. Wasting 100MB in the database for 100 trolling answers isn't going to kill some hungry child in Africa.

codezero4• 13 years ago

I'm probably so serious because it seems like so many other people are so dismissive :)

nilkn• 13 years ago

In terms of responding seriously to someone actually asking for code to sort a list, I completely agree with you. My impression, though, since this is on the Code Golf section of Stack Exchange, is that this is purely hypothetical. It's a challenge to come up with the most evil answer to the question, not as a serious answer to someone asking it but as a puzzle.

pandaman• 13 years ago

Providing a thorough, quality answer to a troll question won't help advance that troll's career, they will pay the price later, for sure, when their intellect is on the line.

This what would happen in an ideal world.

In reality though it's orders of magnitude easier to check credentials than intellect (provided it's even possible to do the later). In many situations, if you go against somebody with credentials without credentials of your own you won't even have a chance to have a battle of wits (like applying for a job that requires a degree).

And cheating will get you credentials most of the time, it's not like universities check every graduate's intellect before issuing them a diploma. Otherwise cheating would not be such a big deal in the academia.

So yes, helping stupid people with their homework will advance their career. Might not to the level of Google's CTO but to the level of the guy who codes healthcare.gov or the DV's "random number generator" or Toyota's ECU or any other example of crappy code that has a good chance to interfere with people's lives. Please don't do that. If you don't want to troll them - just don't reply.

DanBC2• 13 years ago

Everything you say is true. Luckily, none of it applies because no one goes to CodeGolf for homework questions.

CodeGolf will look at other SE sites, find homework questions, then take those questions back to codegolf.

Thus, CodeGolf gets an interesting new flavour of challenge (provide the worst solution to a problem) and the person who originally asked the question doesn't have to deal with the codegolfing. They do, however, have to deal with the rest of SE.

I guess downvotes are because you appear to think that codegolfers are answering in the threads where the questions are originally asked.

codezero4• 13 years ago

Yep, this context helps a lot, I don't know enough about codegolf, thanks!

lmm2• 13 years ago

I downvoted because I disagree with asking for explanations of downvotes. I think the practice is bad for HN.

codezero4• 13 years ago

Makes sense. But for folks who are downvoted it can be helpful to know some context, I've noticed that when you ask for feedback you get it and when you don't you end up confused and a bit pissed which is toxic over time.

I was -1 when I edited the comment to include it and +22 now and a lot less confused.

applecore• 13 years ago

If you don't want to answer the question, don't answer the question.

ChuckMcM2• 13 years ago

Sigh, don't have an SO account but if I did, I would suggest this code which I call randsort --

   #include <stdint.h>
   #include <stdio.h>
   #include <stdlib.h>

   int
   main(int argc, char *argv[]) {
       int i, ndx;
       double my_numbers[10];
       double sorted_numbers[10];
       uint16_t picked;

       for (i = 1; i < argc; i++) {
           my_numbers[i-1] = atof(argv[i]);
       }

       while (1) {
           picked = 0;
           ndx = 0;
           /* sort the numbers */
           while (picked != 0x3ff) {
               i = (rand() / 100) %  10;
               if ((picked & (1 << i)) == 0) {
                   picked |= (1 << i);
                   sorted_numbers[ndx++] = my_numbers[i];
               }
           }

           /* verify they sorted correctly */
           for (i = 8; i >= 0; i--) {
               if (( i == -1) || (sorted_numbers[i] > sorted_numbers[i+1])) {
                   break;
               }
           }
           if (i == -1) {
               printf(" Sorted: \n");
               for (i = 0; i < 10; i++) {
                   printf(" %d: %f\n", i, sorted_numbers[i]);
               }
               exit(0);
           }
       }
   }

demallien• 13 years ago

Nice. Is that O(e^n)?

Out of curiosity, why do you divide the rand() by 100 before applying the mod?

ChuckMcM2• 13 years ago

No reason on the divide. Just because. That is probably a reasonable guess on the big O value. Clearly O(rand) is cheeky but in accurate. And the PRNG will walk the number space so it will eventually succeed, but computing how long it will take for 'n' numbers eludes my math reasoning skills.

akx• 13 years ago

And since `srand(time(NULL))` isn't ever called, it's deterministic, too!

nitrogen• 13 years ago

Is that the case for all platforms and C libraries? Also, isn't seeding with the current time a way to guarantee deterministic behavior? An attacker of such an algorithm probably knows what time it is, and users probably don't expect all invocations within a given second to return the same results.

Houshalter2• 13 years ago

I considered considering this ridiculously over-complicated approximate solution. Train a neural network to sort with a bunch of examples of sorted arrays.

tlarkworthy• 13 years ago

I would be interested if you could expand on how you would alter the NN architecture for different sized lists

Houshalter2• 13 years ago

You would have to deal with a maximum size limit, or sort only sections of it at a time.

I mean it might technically be possible if you did some kind of recurrent neural network and gave the inputs through time rather than through space. And you would also have to let it interact with some kind of external memory or workspace.

Perhaps you could train it to just perform operations on the list itself (compare two elements, swap two elements, etc.) That would be the simplest way.

raverbashing• 13 years ago

My favourite way goes like this

https://gist.github.com/anonymous/8158332

Basically, each thread sleeps for the time corresponding to the number

donquichotte• 13 years ago

Haha, fantastic! This is an implementation in go: https://gist.github.com/anonymous/8158822

xzel• 13 years ago

Even help on the internet is cynical now? Honestly, interesting idea though.

Trolling homework questions - sorting

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