Java BftPD sample cell

CellTemplate.java

/*
 Sample code for a "Battle for the Petri Dish" cell

 Released under the terms of the WTF Public License
 No warranty express or implied is granted, etc, etc.

 I just hacked this together very quickly; improvements are welcome, so please fork the Gist if you like.
*/

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.HashMap;

public class CellTemplate {
    public static final int MAX_HP = 5;
    public static final int MAX_ENERGY = 5;
    public static final int ACIDITY = 2;

    // given arena state and cell stats, return an action string (e.g., "ATTACK NW 2", "DIVIDE S")
    public static String decide(Arena arena, Point cell, int hp, int energy) {
        // empty and corpses are free for movement and division
        ArrayList<Point> nearbyEmpty = arena.getAdjacentMatches(cell, ".");
        nearbyEmpty.addAll(arena.getAdjacentMatches(cell, "c"));

        ArrayList<Point> nearbyEnemies = arena.getAdjacentMatches(cell, "x");
        ArrayList<Point> nearbyCorpses = arena.getAdjacentMatches(cell, "c");
        ArrayList<Point> nearbyFriends = arena.getAdjacentMatches(cell, "o");
        
        // if you have energy and space to divide, divide into a random space
        if(energy >= 5 && nearbyEmpty.size() > 0) {
            Point randomEmpty = nearbyEmpty.get((int)Math.floor(nearbyEmpty.size()*Math.random()));
            return "DIVIDE " + arena.getDirection(cell, randomEmpty);
        }

        // if you have two or more nearby enemies, explode if possible
        if(nearbyEnemies.size() > 1 && energy > hp && hp <= 3) {
            return "EXPLODE";
        }

        // if at least one adjacent enemy, attack if possible
        if(energy > 0 && nearbyEnemies.size() > 0) {
            int attackStrength = Math.min(energy, 3);
            Point enemy = nearbyEnemies.get((int)Math.floor(nearbyEnemies.size()*Math.random()));
            return "ATTACK " + arena.getDirection(cell, enemy) + " " + attackStrength;
        }

        // if there's a nearby corpse, eat it if your energy is below max
        if(nearbyCorpses.size() > 0) {
            Point corpse = nearbyCorpses.get((int)Math.floor(nearbyCorpses.size()*Math.random()));
            return "EAT " + arena.getDirection(cell, corpse);
        }

        return "REST";

    }

    public static void main(String[] args) throws IOException {
        BufferedReader br =
            new BufferedReader(new InputStreamReader(System.in));

        String firstLine;

        firstLine = br.readLine();
        if(firstLine.equals("BEGIN")) {
            System.out.println(MAX_HP + " " + MAX_ENERGY + " " + ACIDITY);
        } else {
            String[] dimensions = firstLine.split(" ");
            int width = Integer.parseInt(dimensions[0]);
            int height = Integer.parseInt(dimensions[1]);
            Point[][] arena = new Point[height][];
            String input;
            int lineno = 0;

            while(!(input=br.readLine()).equals("")) {
                String[] charList = input.substring(1).split("");
                arena[lineno] = new Point[width];
                for(int i=0; i<charList.length; ++i) {
                    arena[lineno][i] = new Point(i, lineno, charList[i]);
                }
                lineno++;
            }

            String[] stats = br.readLine().split(" ");
            int x = Integer.parseInt(stats[0]);
            int y = Integer.parseInt(stats[1]);
            int hp = Integer.parseInt(stats[2]);
            int energy = Integer.parseInt(stats[3]);

            Arena arenaObj = new Arena(arena, width, height);
            System.out.print(decide(arenaObj, arenaObj.get(x,y), hp, energy));
        }
    }

    public static class Arena {
        public Point[][] array;
        public HashMap<String, String> c2d;
        public int height;
        public int width;

        public Arena(Point[][] array, int width, int height) {
            this.array = array;
            this.width = width;
            this.height = height;

            this.c2d = new HashMap<String, String>();
            this.c2d.put("0,0", "-");
            this.c2d.put("0,-1", "N");
            this.c2d.put("0,1", "S");
            this.c2d.put("1,0", "E");
            this.c2d.put("-1,0", "W");
            this.c2d.put("-1,-1", "NW");
            this.c2d.put("1,-1", "NE");
            this.c2d.put("-1,1", "SW");
            this.c2d.put("1,1", "SE");
        }

        // get the character at x,y
        // or return empty string if out of bounds
        public Point get(int x, int y) {
            if(y < 0 || y >= this.array.length){
                return null;
            }

            Point[] row = this.array[y];

            if(x < 0 || x >= row.length) {
                return null;
            }

            return row[x];
        }

        // get arraylist of Points for each adjacent space that matches the target string
        public ArrayList<Point> getAdjacentMatches(Point p, String match) {
            ArrayList<Point> result = new ArrayList<Point>();
            for(int i=-1; i<=1; ++i) {
                for(int j=-1; j<=1; ++j) {
                    Point found = this.get(p.x+i, p.y+j);
                    if((i!=0 || j!=0) && found != null && found.symbol.equals(match)) {
                        result.add(found);
                    }
                }
            }
            return result;
        }

        // get the direction string from point 1 to point 2
        public String getDirection(Point p1, Point p2) {
            int dx = p2.x - p1.x;
            int dy = p2.y - p1.y;
            dx = Math.abs(dx) / (dx==0?1:dx);
            dy = Math.abs(dy) / (dy==0?1:dy);

            return this.c2d.get(dx + "," + dy);
        }

    }

    public static class Point {
        int x, y;
        String symbol;

        public Point(int x, int y, String sym) {
            this.x=x;
            this.y=y;
            this.symbol=sym;
        }
    }
}