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#include "geometry/ccw.hpp"
#pragma once
#include "point.hpp"
namespace geometry {
// http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=CGL_1_C
constexpr int COUNTER_CLOCKWISE = +1;
constexpr int CLOCKWISE = -1;
constexpr int ONLINE_BACK = +2; // c-a-b
constexpr int ONLINE_FRONT = -2; // a-b-c
constexpr int ON_SEGMENT = 0; // a-c-b
int ccw(const Point &a, Point b, Point c) {
b = b - a, c = c - a;
if (sign(cross(b, c)) == +1) return COUNTER_CLOCKWISE;
if (sign(cross(b, c)) == -1) return CLOCKWISE;
if (sign(dot(b, c)) == -1) return ONLINE_BACK;
if (norm(b) < norm(c)) return ONLINE_FRONT;
return ON_SEGMENT;
}
} // namespace geometry
#line 2 "geometry/base.hpp"
namespace geometry {
using Real = double;
const Real EPS = 1e-8;
const Real PI = acos(static_cast<Real>(-1));
enum { OUT, ON, IN };
inline int sign(const Real &r) { return r <= -EPS ? -1 : r >= EPS ? 1 : 0; }
inline bool equals(const Real &a, const Real &b) { return sign(a - b) == 0; }
} // namespace geometry
#line 3 "geometry/point.hpp"
namespace geometry {
using Point = complex<Real>;
istream &operator>>(istream &is, Point &p) {
Real a, b;
is >> a >> b;
p = Point(a, b);
return is;
}
ostream &operator<<(ostream &os, const Point &p) {
return os << real(p) << " " << imag(p);
}
Point operator*(const Point &p, const Real &d) {
return Point(real(p) * d, imag(p) * d);
}
// rotate point p counterclockwise by theta rad
Point rotate(Real theta, const Point &p) {
return Point(cos(theta) * real(p) - sin(theta) * imag(p),
sin(theta) * real(p) + cos(theta) * imag(p));
}
Real cross(const Point &a, const Point &b) {
return real(a) * imag(b) - imag(a) * real(b);
}
Real dot(const Point &a, const Point &b) {
return real(a) * real(b) + imag(a) * imag(b);
}
bool compare_x(const Point &a, const Point &b) {
return equals(real(a), real(b)) ? imag(a) < imag(b) : real(a) < real(b);
}
bool compare_y(const Point &a, const Point &b) {
return equals(imag(a), imag(b)) ? real(a) < real(b) : imag(a) < imag(b);
}
using Points = vector<Point>;
} // namespace geometry
#line 3 "geometry/ccw.hpp"
namespace geometry {
// http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=CGL_1_C
constexpr int COUNTER_CLOCKWISE = +1;
constexpr int CLOCKWISE = -1;
constexpr int ONLINE_BACK = +2; // c-a-b
constexpr int ONLINE_FRONT = -2; // a-b-c
constexpr int ON_SEGMENT = 0; // a-c-b
int ccw(const Point &a, Point b, Point c) {
b = b - a, c = c - a;
if (sign(cross(b, c)) == +1) return COUNTER_CLOCKWISE;
if (sign(cross(b, c)) == -1) return CLOCKWISE;
if (sign(dot(b, c)) == -1) return ONLINE_BACK;
if (norm(b) < norm(c)) return ONLINE_FRONT;
return ON_SEGMENT;
}
} // namespace geometry