nmalaguti's Halite Bots

Code Organization

I started out with a few different programming languages. As you go through the commit history you'll see different top level directories for different languages.

Notably:

• javascript contains many of the bots in my tutorial
• python early attempts at bots, eventually used as a way to bootstrap other languages
• java basically just a simple bot before I switched to Kotlin
• kotlin the majority of my bots

There are also some other projects that started as subdirectories. Some were eventually split into their own standalone community tools.

Notably:

• halite-lite became mini-halite
• aws was the source for CloudBots
• tournament was a script I wrote to run local tournaments between my bots. I eventually wrote mini-halite as an alternative. It also contains some python code for quick iteration on ideas and a script to upload bots to a server of mine that was always running matches.

Building The Kotlin Bot

You'll need a Java 8+ JDK installed. I use Gradle to compile and package my bot.

To build a zip for upload:

$ cd kotlin
$ ./gradlew cleanDistZip distZip

This will make a MyBot.zip file in kotlin/build/distributions/.

To build a jar that can be used directly:

$ cd kotlin
$ ./gradlew installDist

This will make a MyBot.jar file in kotlin/build/install/MyBot/.

To run the jar: java -jar MyBot.jar

Evolution Of My Bots

From BetterBot to FrugalBot

These bots are my original inspiration for the "So you've Improved the Random Bot. Now what?" tutorial.

The tutorial basically chronicles my approach to building them. Notable differences were that I was using strength / (production * production) instead of just strength / production that I switched to later. I thought that production would be more valuable over time so it should be more heavily weighted, but it turns out that the straight ratio worked out better.

These bots had some improvements over OverkillBot:

• Joint moves so that 2 pieces next to an environment piece could capture it sooner
• Abandon moves so that a piece would move somewhere else if its objective would take too long to capture
• Assist moves so that a piece would help a neighbor capture a nearby piece
• Wastage prevention to avoid combining pieces above the 255 cap - this was super hacky and did not work great

I also played around with A* and other ways to try to get the "pathing" or "tunneling" behavior that djma has. None of them were very effective and although the code is there, it went mostly unused in my submitted bots.

Crossing the Chasm: LazyBot

I spent what felt like an eternity (but was more like 4 days) trying to move away from blob-like OverkillBot behavior and switch to something that could tunnel.

I eventually landed on building a BFS grid where I assigned a value to every border cell and then walked the BFS grid inward increasing each cells value by 1 each time. This worked much better than FrugalBot and was the starting point for the rest of my bots.

From DoubleBot to ThugBot

Final Ranking Of My Bots

Bot	Mu	Sigma	Score	Games
disallowedshovebot	31.848	0.704	29.735	643
disallowedshoveprodbot	30.833	0.703	28.724	622
parametermixbot	30.815	0.701	28.713	2008
claimcombatbot	30.738	0.683	28.689	1746
waittoattackbot	30.480	0.684	28.428	2086
sharpfocusbot	30.451	0.687	28.389	4598
sharpparametermixbot	30.218	0.680	28.178	1666
variabledirwalkbot	30.209	0.683	28.161	2079
shovecrossnotclaimbot	30.205	0.692	28.130	996
parametermixwaitmorebot	29.844	0.732	27.650	119
shoveblackoutbot	29.672	0.691	27.599	1148
punchthroughbot	29.404	0.675	27.380	1547
sharpparametermix2bot	29.398	0.683	27.350	1632
minvariabledirwalkbot	29.183	0.672	27.167	2116
focusbot	29.068	0.682	27.023	4901
purenapbot	28.926	0.677	26.893	5248
contactsquaredbot	28.871	0.672	26.856	3707
inbetweensquaredbot	28.841	0.683	26.792	2084
boxofrocksblackoutbot	28.732	0.683	26.682	462
shovestrict64mixbot	28.775	0.703	26.667	207
shovestrict64bot	28.794	0.711	26.661	192
finebattlebotv2-nobruise	28.501	0.684	26.450	6702
napbot	28.395	0.680	26.354	5076
shovecrossbot	28.281	0.687	26.220	1000
shovebetterbattlebot	28.220	0.684	26.169	1098
krakenbot	28.212	0.682	26.167	4632
justsquaredbot	28.178	0.684	26.126	3470
boxofrocksequalbot	28.246	0.710	26.116	158
thugclassicduobot	28.137	0.682	26.090	1234
thugclassicpunchbot	27.943	0.687	25.882	1092
finebattlebotv2	27.910	0.688	25.846	6653
shoveoldstylebot	27.944	0.713	25.805	146
thugclassicbot	27.803	0.682	25.757	1188
spaghettistillbot	27.785	0.703	25.675	594
shovebot	27.675	0.692	25.600	161
spaghettibot	27.478	0.727	25.298	114
superhungrybot	27.313	0.689	25.244	5816
idlestrengthbotv8	27.261	0.695	25.175	6704
canidobetterbotv19	27.173	0.683	25.123	6952
purestrengthbot	27.124	0.682	25.079	5158
thugclassicanyduobot	26.883	0.690	24.813	1196
compressbugfixbot	26.808	0.685	24.754	5229
lastgaspbot	27.174	0.833	24.677	66
spartanbot	26.639	0.682	24.594	5287
shovefinerbattlebot	26.675	0.734	24.474	118
lastgasptoobot	27.123	0.887	24.463	59
compressbot	26.484	0.686	24.425	5411
hungrybot	26.456	0.679	24.420	4920
orientationbot	25.625	0.678	23.590	4732
fighterbot	25.011	0.691	22.938	4000
shoveblackborderbot	25.596	0.906	22.879	52
boxofrocksbot	26.546	1.266	22.747	23
thugbot	23.086	0.702	20.979	3544
blacklistbot	21.453	0.735	19.249	3648
doublebot	20.607	0.738	18.392	3844
swarmbot	18.528	0.766	16.230	3327

Bot Development Process

Final Bot Code In Detail