Bot show and tell: sometypes

[miangraham]

Here's mine: https://github.com/miangraham/bombercrab-player

The diff has lots of noise from building on nixos but all the meat is in lib.rs.

I added a postmortem commit to clean up the worst of the hacky code duplication and add train-of-thought comments for the curious. No logic changes since pizza night (edit: actually one tiny oversight fixed). But if you want to see the mess as it was, check out my HEAD~1.

General approach:

• Deliberately avoid A*, numerical heuristics, and new non-std libraries. For fun and coding speed.
• Cache observed info on world. Required due to fog of war.
• Stateless behavior. No plans held across ticks.
• Pathfinding: Multi-pass BFS with changing objectives and criteria for tile traversability.
• Accidental pacifist: No attempt to actively attack others or go after powerups, due to time constraints.
• DRY ignored for maximum hacking. BFS code copy-pasted many times, then cleaned up in this postmortem.

Outstanding bugs:

• No consideration of fuse time. Wanted to bake these into a list-per-coord of future explosion times.
• Objects that have left visibility aren't considered for movement/safety. Causes occasional suicide.
• Using stateless BFS sometimes causes routes to oscillate between two different directions and get stuck.
  With more time available, either switch to A* or retain an intended path across ticks.

If I'd heard about the event sooner and had a couple days to work instead of starting day-of, I would have done better object memory and explosion prediction, and probably switched to A* to do soft crate avoidance via heuristic. This approach was plenty of fun though!

Thanks for the great event. Hopefully I'll make it in person next time!