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Comment by 1amzave | Hacker News Reader

So what languages did everyone use?

I decided to try a different one on each level, so I used Python, bash (letting GNU coreutils 'factor' do the hard work), and Haskell, respectively.

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JavaScript. I had my browser open ... it seemed like the logical place. :)

Common Lisp of course :-)

I used Haskell for the first one (was my first actual Haskell program, everything before was just xmonad config), C for the second one (already had the needed code for generating fibonacci sequences and a prime number sieve from when I went through the euler problems using only ANSI C) and Perl for the last one. I initially used Data::PowerSet for the Perl code, but decided to write my own after it took several minutes to build the combinations and I discovered that I had the wrong answer because I improperly read the problem.

I should note that I used the existing C code I had because I had no idea where they would intersect and didn't feel like writing Yet Another Arbitrarily Large Integer Handler.

Ruby was my main choice + some command line tools to do bits of extra work, like 'sort' to find the largest palindrome and 'wc' to count the results in last exercise, and even Python command line to just manually sum the primes in second exercise.

Ruby has Array#sort, no command line required.

I used Lua, myself. I briefly considered using a more featureful language like Ruby, but I'm happy to say that Lua did the job just fine. I made good use of coroutines for the second and third problems.

Python, Scheme, Python. Mainly because I had nice functions in Scheme for level 2 sitting around from when I was trying to work through SICP...

I know I'm late to the party, :) I used Ruby 1.9.2. It's funny that it's the first time I used the combination generation method built in Ruby Array. The whole three questions took me about a bit more than 20 minutes, a bit longer than I thought tho.

Matlab for all three parts.

Quick and dirty solutions here: http://gist.github.com/618006

I'm wonderfully amazed that coreutils has factor.

Python for 1,2 with a little bit of manual pasting into wolfram alpha

And for part 3 I used prolog. About ~6 lines or so.

Clojure here.

Mind posting your solution as a Gist? I want to see how to do level 1 without explicit loops or variables.

Sure, sorry about the delay.

http://gist.github.com/621130

I can't take credit for the solution I posted though.

I originally wrote a naive O(N^2) complexity solution (which was much shorter and was fine for the length of the input) I had this palindrome code in my 'toolbox' of code I've come across though, I'm afraid I don't know the orig author.

I just tweaked it as this is more in line with the type of example you're looking for.

Interesting, I'll have to go over your code fairly carefully, as I'm not familiar with every technique you're using here for performance.

I've since learned a good deal about Clojure and implemented an idiomatic (but probably less performant) version, for anyone interested in how short this can be:

http://gist.github.com/635674

Perl. From the look of this thread, I guess everyone else has moved on?

I solved all three in Perl 6... ;)

Python here - very quick to code in if you have terminal handy.

Haskell for all. Perfect fit.

k, javascript, javascript

None of my solutions were particularly elegant :-)

No Erlang?!

c / python

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