Coordinate.java

package code.advent.day4;

/**
 * Created by Nick on 12/3/2015.
 */
public class Coordinate {
    public int x;
    public int y;

    public Coordinate(int x, int y) {
        this.x = x;
        this.y = y;
    }

    public void add(Coordinate coordinate) {
        this.x += coordinate.x;
        this.y += coordinate.y;
    }

    @Override
    public String toString() {
        return "Coordinate{" +
                "x=" + x +
                ", y=" + y +
                '}';
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;

        Coordinate that = (Coordinate) o;

        if (x != that.x) return false;
        if (y != that.y) return false;

        return true;
    }

    @Override
    public int hashCode() {
        int result = x;
        result = 31 * result + y;
        return result;
    }
}

solve.java

package code.advent.day4;

import java.io.File;
import java.io.FileNotFoundException;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Scanner;

/**
 * Created by Nick on 12/3/2015.
 */
public class solve {
    public static void main(String[] args) throws FileNotFoundException {
        Scanner scan = new Scanner(new File("input.txt"));
        String input = scan.nextLine();
        Coordinate coordinate = new Coordinate(0, 0);

        HashMap<Character, Coordinate> hashMap = new HashMap<>();
        hashMap.put('^', new Coordinate(0,1));
        hashMap.put('v', new Coordinate(0,-1));
        hashMap.put('<', new Coordinate(-1,0));
        hashMap.put('>', new Coordinate(1,0));

        HashSet<Coordinate> hashSet = new HashSet();

        for (int i = 0; i < input.length(); i++) {
            hashSet.add(new Coordinate(coordinate.x, coordinate.y));
            coordinate.add(hashMap.get(input.charAt(i)));
        }
        hashSet.add(new Coordinate(coordinate.x, coordinate.y));

        System.out.println(hashSet.size());
    }
}