#define PROBLEM "http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=CGL_3_B" #include <iomanip> #include <iostream> #include "Mylib/Geometry/Float/double_eps.cpp" #include "Mylib/Geometry/Float/geometry_template.cpp" #include "Mylib/Geometry/Float/is_convex.cpp" #include "Mylib/IO/input_vector.cpp" namespace hl = haar_lib; static constexpr double eps = 1e-7; using D = hl::double_eps<double, eps>; int main() { int n; std::cin >> n; hl::polygon<D> p = hl::input_vector<hl::point<D>>(n); std::cout << (hl::is_convex(p) ? 1 : 0) << std::endl; return 0; }
#line 1 "test/aoj/CGL_3_B/main.test.cpp" #define PROBLEM "http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=CGL_3_B" #include <iomanip> #include <iostream> #line 2 "Mylib/Geometry/Float/double_eps.cpp" #include <cmath> #line 4 "Mylib/Geometry/Float/double_eps.cpp" #include <limits> namespace haar_lib { template <typename T, const T &eps> struct double_eps { using value_type = T; private: T value_; public: double_eps() : value_(0) {} double_eps(T value_) : value_(value_) {} auto &operator=(const double_eps &rhs) { this->value_ = rhs.value_; return *this; } auto &operator+=(const double_eps &rhs) { this->value_ += rhs.value_; return *this; } auto &operator-=(const double_eps &rhs) { this->value_ -= rhs.value_; return *this; } auto &operator*=(const double_eps &rhs) { this->value_ *= rhs.value_; return *this; } auto &operator/=(const double_eps &rhs) { this->value_ /= rhs.value_; return *this; } auto operator+(const double_eps &rhs) const { return double_eps(this->value_ + rhs.value_); } auto operator-(const double_eps &rhs) const { return double_eps(this->value_ - rhs.value_); } auto operator*(const double_eps &rhs) const { return double_eps(this->value_ * rhs.value_); } auto operator/(const double_eps &rhs) const { return double_eps(this->value_ / rhs.value_); } bool operator==(const double_eps &rhs) const { return std::abs(this->value_ - rhs.value_) < eps; } bool operator!=(const double_eps &rhs) const { return !(*this == rhs); } bool operator<(const double_eps &rhs) const { return this->value_ - rhs.value_ < -eps; } bool operator<=(const double_eps &rhs) const { return this->value_ - rhs.value_ < eps; } bool operator>(const double_eps &rhs) const { return !(*this <= rhs); } bool operator>=(const double_eps &rhs) const { return !(*this < rhs); } auto operator-() const { return double_eps(-(this->value_)); } explicit operator double() const noexcept { return value_; } explicit operator long double() const noexcept { return value_; } friend std::ostream &operator<<(std::ostream &s, const double_eps &rhs) { s << rhs.value_; return s; } friend std::istream &operator>>(std::istream &s, double_eps &rhs) { s >> rhs.value_; return s; } friend double_eps sin(double_eps x) { return std::sin((T) x); } friend double_eps cos(double_eps x) { return std::cos((T) x); } friend double_eps tan(double_eps x) { return std::tan((T) x); } friend double_eps acos(double_eps x) { return std::acos((T) x); } friend double_eps atan2(double_eps y, double_eps x) { return std::atan2((T) y, (T) x); } friend double_eps abs(double_eps x) { return std::abs((T) x); } friend double_eps sqrt(double_eps x) { return std::sqrt(std::max<T>(0, (T) x)); } }; } // namespace haar_lib namespace std { template <typename T, const T &eps> class numeric_limits<haar_lib::double_eps<T, eps>> { public: static haar_lib::double_eps<T, eps> infinity() { return numeric_limits<T>::infinity(); } static haar_lib::double_eps<T, eps> min() { return numeric_limits<T>::min(); } static haar_lib::double_eps<T, eps> max() { return numeric_limits<T>::max(); } static haar_lib::double_eps<T, eps> lowest() { return numeric_limits<T>::lowest(); } }; } // namespace std #line 4 "Mylib/Geometry/Float/geometry_template.cpp" #include <vector> namespace haar_lib { template <typename T> struct vec { T x, y; vec() {} vec(T x, T y) : x(x), y(y) {} friend auto operator+(const vec &a, const vec &b) { return vec(a.x + b.x, a.y + b.y); } friend auto operator-(const vec &a, const vec &b) { return vec(a.x - b.x, a.y - b.y); } friend auto operator-(const vec &a) { return vec(-a.x, -a.y); } friend bool operator==(const vec &a, const vec &b) { return a.x == b.x and a.y == b.y; } friend bool operator!=(const vec &a, const vec &b) { return !(a == b); } friend bool operator<(const vec &a, const vec &b) { return a.x < b.x or (a.x == b.x and a.y < b.y); } friend std::istream &operator>>(std::istream &s, vec &a) { s >> a.x >> a.y; return s; } }; template <typename T, typename U> auto operator*(const vec<T> &a, const U &k) { return vec<T>(a.x * k, a.y * k); } template <typename T, typename U> auto operator*(const U &k, const vec<T> &a) { return vec<T>(a.x * k, a.y * k); } template <typename T, typename U> auto operator/(const vec<T> &a, const U &k) { return vec<T>(a.x / k, a.y / k); } template <typename T> using point = vec<T>; template <typename T> T abs(const vec<T> &a) { return sqrt(a.x * a.x + a.y * a.y); } template <typename T> T abs_sq(const vec<T> &a) { return a.x * a.x + a.y * a.y; } template <typename T> T dot(const vec<T> &a, const vec<T> &b) { return a.x * b.x + a.y * b.y; } template <typename T> T cross(const vec<T> &a, const vec<T> &b) { return a.x * b.y - a.y * b.x; } template <typename T> auto unit(const vec<T> &a) { return a / abs(a); } template <typename T> auto normal(const vec<T> &p) { return vec<T>(-p.y, p.x); } template <typename T> auto polar(const T &r, const T &ang) { return vec<T>(r * cos(ang), r * sin(ang)); } template <typename T> T angle(const vec<T> &a, const vec<T> &b) { return atan2(b.y - a.y, b.x - a.x); } template <typename T> T phase(const vec<T> &a) { return atan2(a.y, a.x); } template <typename T> T angle_diff(const vec<T> &a, const vec<T> &b) { T r = phase(b) - phase(a); if (r < -M_PI) return r + 2 * M_PI; else if (r > M_PI) return r - 2 * M_PI; return r; } template <typename T> struct line { point<T> from, to; line() : from(), to() {} line(const point<T> &from, const point<T> &to) : from(from), to(to) {} }; template <typename T> using segment = line<T>; template <typename T> auto unit(const line<T> &a) { return unit(a.to - a.from); } template <typename T> auto normal(const line<T> &a) { return normal(a.to - a.from); } template <typename T> auto diff(const segment<T> &a) { return a.to - a.from; } template <typename T> T abs(const segment<T> &a) { return abs(diff(a)); } template <typename T> T dot(const line<T> &a, const line<T> &b) { return dot(diff(a), diff(b)); } template <typename T> T cross(const line<T> &a, const line<T> &b) { return cross(diff(a), diff(b)); } template <typename T> using polygon = std::vector<point<T>>; template <typename T> struct circle { point<T> center; T radius; circle() : center(), radius(0) {} circle(const point<T> ¢er, T radius) : center(center), radius(radius) {} }; template <typename T> std::ostream &operator<<(std::ostream &s, const vec<T> &a) { s << "(" << a.x << ", " << a.y << ")"; return s; } template <typename T> std::ostream &operator<<(std::ostream &s, const line<T> &a) { s << "(" << a.from << " -> " << a.to << ")"; return s; } template <typename T> std::ostream &operator<<(std::ostream &s, const circle<T> &a) { s << "(" << "center: " << a.center << ", " << "radius: " << a.radius << ")"; return s; } } // namespace haar_lib #line 3 "Mylib/Geometry/Float/ccw.cpp" namespace haar_lib { namespace ccw_impl { enum status { ONLINE_BACK = -2, COUNTER_CLOCKWISE = -1, ON_SEGMENT = 0, CLOCKWISE = 1, ONLINE_FRONT = 2 }; } struct ccw { ccw_impl::status value; bool operator==(const ccw &that) const { return value == that.value; }; bool operator!=(const ccw &that) const { return value != that.value; }; bool is_online_back() const { return value == ccw_impl::status::ONLINE_BACK; } bool is_counter_clockwise() const { return value == ccw_impl::status::COUNTER_CLOCKWISE; } bool is_on_segment() const { return value == ccw_impl::status::ON_SEGMENT; } bool is_clockwise() const { return value == ccw_impl::status::CLOCKWISE; } bool is_online_front() const { return value == ccw_impl::status::ONLINE_FRONT; } }; template <typename T> ccw check_ccw(const point<T> &p0, const point<T> &p1, const point<T> &p2) { using namespace ccw_impl; const T cr = cross(p1 - p0, p2 - p0); const T d = dot(p1 - p0, p2 - p0); if (cr == 0) { if (d < 0) return ccw({ONLINE_BACK}); else if (abs(p2 - p0) > abs(p1 - p0)) return ccw({ONLINE_FRONT}); else return ccw({ON_SEGMENT}); } else if (cr > 0) { return ccw({COUNTER_CLOCKWISE}); } else { return ccw({CLOCKWISE}); } } } // namespace haar_lib #line 5 "Mylib/Geometry/Float/is_convex.cpp" namespace haar_lib { template <typename T> bool is_convex(const polygon<T> &ps) { const int n = ps.size(); std::vector<ccw> temp; for (int i = 0; i < n; ++i) { const auto c = check_ccw(ps[i], ps[(i + 1) % n], ps[(i + 2) % n]); if (c.is_clockwise() or c.is_counter_clockwise()) { if (temp.empty()) temp.push_back(c); else if (temp.back() != c) return false; } } return true; } } // namespace haar_lib #line 4 "Mylib/IO/input_vector.cpp" namespace haar_lib { template <typename T> std::vector<T> input_vector(int N) { std::vector<T> ret(N); for (int i = 0; i < N; ++i) std::cin >> ret[i]; return ret; } template <typename T> std::vector<std::vector<T>> input_vector(int N, int M) { std::vector<std::vector<T>> ret(N); for (int i = 0; i < N; ++i) ret[i] = input_vector<T>(M); return ret; } } // namespace haar_lib #line 9 "test/aoj/CGL_3_B/main.test.cpp" namespace hl = haar_lib; static constexpr double eps = 1e-7; using D = hl::double_eps<double, eps>; int main() { int n; std::cin >> n; hl::polygon<D> p = hl::input_vector<hl::point<D>>(n); std::cout << (hl::is_convex(p) ? 1 : 0) << std::endl; return 0; }