I am attempting to assign a color to each of the states so that no two adjacent states share the same color (http://en.wikipedia.org/wiki/Four_color_theorem). The program will output each state and its color.

I'm reading in a text file with the following format for 48 states (2 aren't connected):

al,fl,ms,tn,ga
ar,la,tx,ok,mo,tn,ms
az,ca,nv,ut,nm
ca,az,nv,or
co,wy,ut,nm,ok,ks,ne
...

Example:

Alabama touches Florida, Mississippi, Tennessee, and Georgia.

Arkansas touches Louisiana, Texas, etc.

This is my code so far:

MapColor.java    

import java.io.*;
import java.util.*;

public class MapColor {

    public static void main(String[] args) throws IOException {

        ArrayList  statestemp = new ArrayList  ();
        ArrayList  states = new ArrayList  ();

        // read in each line
        BufferedReader reader = new BufferedReader(new FileReader("usa.txt"));
        String line = null;
        while ((line = reader.readLine()) != null) {
            statestemp.add(line);
        }
        reader.close();

        // create all state objects and adjacencies
        for (int i = 0; i < statestemp.size(); i++) {
            State st = new State();
            String[] str = statestemp.get(i).split(",");
            st.setName(str[0]);
            for (int j = 1; j < str.length; j++) {
                st.addAdj(str[j]);
            }
            states.add(st);
        }

        // set colors


        // print out states and adjacencies
        for (State s : states) {
            System.out.println("Name: " + s.getName());
            System.out.println("Color: " + s.getColor());
            System.out.print("Adj: ");
            s.getAdj();
            System.out.println();
            System.out.println();
        }

    }
}

and

State.java

import java.util.ArrayList;

public class State {

    public String n = null;
    public int c = 0;
    public ArrayList  adj = new ArrayList  ();

    public String getName() {
        return n;
    }
    public void setName(String name) {
        this.n = name;
    }
    public int getColor() {
        return c;
    }
    public void setColor(int color) {
        this.c = color;
    }
    public void addAdj(String s) {
        this.adj.add(s);
    }
    public ArrayList  getAdj() {
        return this.adj;
    }
}

I am at the point where I would like to begin assigning colors, but I am unsure how to go about making comparisons.

Any suggestions would be appreciated!