计算几何模板（建设中）

geometry.cpp

template <typename T>
T sq(const T &a){return a * a;}

using ldb = long double;
struct pnt{
    ldb x, y;
    ldb len()const{
        return std::sqrt(x * x + y * y);
    }
    ldb len2()const{
        return x * x + y * y;
    }
    pnt operator-(const pnt &other)const{
        return {x - other.x, y - other.y};
    }
    void read(){cin >> x >> y;}
};

struct rect{
    pnt p[2];
    void read(){p[0].read(), p[1].read();}
    bool cover(const pnt &a)const{
        return p[0].x <= a.x && a.x <= p[1].x && p[0].y <= a.y && a.y <= p[1].y;
    }
};

struct seg{
    pnt a, b;
    void read(){a.read(), b.read();}
};

struct circ{
    pnt c;
    ldb r;
    void read(){c.read(); cin >> r;}
    bool cover(const pnt &p)const{
        return (p - c).len2() <= r * r;
    }
    bool is_cross(const seg &a, pnt *res = nullptr)const { //未完成
        if(cover(a.a) && cover(a.b)) return true;
    }
};