Project Euler “is a series of challenging
mathematical/computer programming problems that will require more than
just mathematical insights to solve.” In other words, you need to get
down and program to solve the problem[1].

I’ve recently reached Level 3 (solved over 100 problems) and thought
I’d share some notes on what I’ve learned.

PE programming is “pure” programming, as in you’re working with
algorithms and not systems. There’s rarely anything more complicated
than file access needed. In fact, I’d say you need an aptitude for
problem solving rather than programming, and the skills needed to
solve PE problems are probably not really translatable to real work
out in the real world, where you’re dealing with real people and real
hardware and networks. To be sure, nowhere on PE do they say that this
is programming in the wider sense, as opposed to Computer Science, but
you’d be surprised how many CS grads think it does (I’m mocking you,
Haskell nerds!).

The typical PE problem looks amenable to brute force, but it pays to
research before jumping in. Wikipedia and Mathworld are great
resources for a lot of the problems, often explaining the math behind
them and sometimes having the algorithms you need.

Spoilers. I find it pretty hard to concentrate on a problem and not
want to know the solution, especially when I’m into “grind” mode and
just want to level up (this happens a lot with me and puzzle games
too). There are plenty of spoilers around for the early problems (the
ones that most people manage to solve) but as you move up they get
sparser and sparser, and are usually in languages other than your
chosen one. Often it’s enough for me to just get a hint. After you’ve
solved a problem, you get access to a forum where others discuss their
solutions. This can be an eye opener, but there’s no need to share
your crappy solution if you don’t want to.

I use Perl. I thought of using PE to learn another language (Python),
but finally I felt it was more fun to explore something I’m pretty
proficient in than to learn something else. Perl has all the things
you need for these problems (so far), especially as there are tons of
libraries for specific applications. One of the more useful is
Math::Pari, an interface to the Pari suite of numerical algorithms.

Perl is really nice for stuff like string manipulation and set
operations. It’s also really easy to build ad-hoc data structures,
although the syntax grows hairy really fast.

Python seems very popular among PE participants. Another popular
language among the people who bother to post to answer threads is
J), and of
course Haskell has some vocal devotees.

I find it challenging and fun to work on these problems, and I
encourage you to do the same!

[1] although there are some wizards who manage with pencil and paper,
at least for the earlier problems.