class Entity {
public:
    int x, y;
    bool alive;
    // Distance squared
    inline int distance2 (const Entity &e) {
        return (x - e.x)*(x - e.x) + (y - e.y)*(y - e.y);
    }
    // Distance square rooted
    inline float distance (Entity *e) {
        return sqrt(distance2(*e));
    }

    inline float distance (int value) {
        return sqrt(value);
    }

    // Distance squared from given point
    inline int distance2 (int _x, int _y) {
        return (x - _x)*(x - _x) + (y - _y)*(y - _y);
    }

    // Distance square from given point
    inline float distance (int _x, int _y) {
        return sqrt(distance2(_x,_y));
    }
};