@@ -0,0 +1,695 @@
+package math;%0A%0Aimport static java.lang.Math.sqrt;%0A%0A/**%0A * Created by Kang SangHun on 2015-04-27.%0A */%0Apublic class Vector %7B%0A    public double x, y;%0A%0A    public Vector() %7B%0A    %7D%0A%0A%0A    public Vector(double _x, double _y) %7B%0A        x = _x;%0A        y = _y;%0A    %7D%0A%0A    public double length() %7B%0A        return sqrt(x * x + y * y);%0A    %7D%0A%0A    public void normalize()%7B%0A        double l = length();%0A        x = x/l;%0A        y = y/l;%0A    %7D%0A    public void add(Vector v)%7B%0A        x+=v.x;%0A        y+=v.y;%0A    %7D%0A%0A    public static Vector add(Vector v1,Vector v2)%7B%0A        return new Vector(v1.x+v2.x,v1.y+v2.y);%0A    %7D%0A%0A    public static double dot(Vector a, Vector b)%7B%0A        return a.x*b.x+a.y*b.y;%0A    %7D%0A%7D%0A

add math Vector file