Priorities for your bot
In 2014, I think that the best bots were the best because they did three things well: combat micro, pathfinding, and strategy.
I
list these in order of importance. To win, you absolutely need top
tier combat micro. You can't afford to fall behind in this area,
or a better team will wipe your robots off the map regardless of your
strategy.
Almost
as important, you need robust pathfinding. Many games were lost
because one team got some or all of their robots stuck behind a
convoluted obstacle, allowing the other team to pick up a free win.
Note that I say "robust" and not "optimal." It's
much more important that you not get stuck than that you get to the
destination as fast as possible. A well-implemented bug nav is much,
much better than a buggy A*.
Finally,
you need good strategy. While you do need to keep up with the
metagame, robust execution is again most important. My bots made some
suboptimal strategic choices in the final tournament but managed to
claw back many of those games because the other teams' bots got
confused or distracted and stopped making progress toward the goal of
collecting milk. Your robots always have to being doing something
sensible even if you are losing or the enemy is doing something
unexpected.
At
least, that's how it was in 2014! If the game doesn't change too
much, I expect that these will continue to be important priorities in
the future.
How to write a winning bot
So
how can you write a bot that wins? The most important rule is: copy
other teams! If you lose a scimmage match, don't be proud.
Copy the technique that beat you, whether it's a new strategy or a
combat micro refinement, and start using it. This will also let you
start developing counters to that technique, using your
implementation as a test opponent.
Make
it easy to write lots of code fast. You are going to have to write
(and rewrite, and rewrite) a few thousand lines of code in just a few
weeks. This is not a lot of time, so you need to make it as easy as
possible to write code efficiently. Use a nice IDE. Wrap the API in
easy-to-use interfaces. I found it particularly useful to wrap the
communications functions and debugging functions in nicer interfaces.
Don't do premature bytecode optimization. Try to have a sense of which parts of your code cost a lot of bytecodes, but don't work too hard on optimizing them early on when they are still likely to change.
Test
a lot. Keep a lot of versions of your bot around and play your
current version against others to test your improvements. Implement
other strategies and test your strategy against those. I probably
spent similar amounts of time coding and watching test matches
between different versions of my bots. By the end of Battlecode 2014
I had 46 different versions lying around that I had used for testing
at various points. The most rigorous testing ground is the scrimmage
server because other teams' bots will behave in unexpected ways and
you get to see whether your code can handle it. Keep in mind that the
goal of testing is to see your bot lose: losing tells you what you
need to fix and improve. So prefer to play scrimmages on your weakest
maps. Fix all the bugs and problems you find in your
testing, unless you make a careful and considered decision that the
bug is too rare or minor to matter. Unfixed bugs will come back to
bite you in tournaments.
