test/verify/aoj-cgl-4-b.test.cpp

View this file on GitHub
Last update: 2026-08-10 10:57:54+00:00
Problem: http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=CGL_4_B

Depends on

Code

// clang-format off
// competitive-verifier: PROBLEM http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=CGL_4_B
// clang-format on
// competitive-verifier: ERROR 0.00000001

#include <complex>
#include <iomanip>
#include <iostream>

#include "../../geometry/convex_polygon_diameter.hpp"

using namespace std;
using namespace geometry;

int main() {
  cout << fixed << setprecision(10);
  int N;
  cin >> N;
  Polygon p(N);
  for (int i = 0; i < N; i++) {
    cin >> p[i];
  }
  auto ret = convex_polygon_diameter(p);
  cout << abs(p[ret.first] - p[ret.second]) << "\n";
}

#line 1 "test/verify/aoj-cgl-4-b.test.cpp"
// clang-format off
// competitive-verifier: PROBLEM http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=CGL_4_B
// clang-format on
// competitive-verifier: ERROR 0.00000001

#include <complex>
#include <iomanip>
#include <iostream>

#line 2 "geometry/convex_polygon_diameter.hpp"

#include <algorithm>
#line 5 "geometry/convex_polygon_diameter.hpp"
#include <utility>

#line 2 "geometry/point.hpp"

#include <cmath>
#line 6 "geometry/point.hpp"
#include <vector>

#line 2 "geometry/base.hpp"

#line 4 "geometry/base.hpp"

namespace geometry {
using Real = double;
const Real EPS = 1e-8;
const Real PI = std::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 9 "geometry/point.hpp"

namespace geometry {
using Point = std::complex<Real>;

std::istream& operator>>(std::istream& is, Point& p) {
  Real a, b;
  is >> a >> b;
  p = Point(a, b);
  return is;
}

std::ostream& operator<<(std::ostream& os, const Point& p) {
  return os << std::real(p) << " " << std::imag(p);
}

Point operator*(const Point& p, const Real& d) {
  return Point(std::real(p) * d, std::imag(p) * d);
}

// rotate point p counterclockwise by theta rad
Point rotate(Real theta, const Point& p) {
  return Point(std::cos(theta) * std::real(p) - std::sin(theta) * std::imag(p),
               std::sin(theta) * std::real(p) + std::cos(theta) * std::imag(p));
}

Real cross(const Point& a, const Point& b) {
  return std::real(a) * std::imag(b) - std::imag(a) * std::real(b);
}

Real dot(const Point& a, const Point& b) {
  return std::real(a) * std::real(b) + std::imag(a) * std::imag(b);
}

bool compare_x(const Point& a, const Point& b) {
  return equals(std::real(a), std::real(b)) ? std::imag(a) < std::imag(b)
                                            : std::real(a) < std::real(b);
}

bool compare_y(const Point& a, const Point& b) {
  return equals(std::imag(a), std::imag(b)) ? std::real(a) < std::real(b)
                                            : std::imag(a) < std::imag(b);
}

using Points = std::vector<Point>;
}  // namespace geometry
#line 2 "geometry/polygon.hpp"

#line 4 "geometry/polygon.hpp"

#line 6 "geometry/polygon.hpp"

namespace geometry {
using Polygon = std::vector<Point>;
using Polygons = std::vector<Polygon>;
}  // namespace geometry
#line 9 "geometry/convex_polygon_diameter.hpp"

namespace geometry {
// http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=CGL_4_B
std::pair<int, int> convex_polygon_diameter(const Polygon& p) {
  int N = (int)p.size();
  int is = 0, js = 0;
  for (int i = 1; i < N; i++) {
    if (std::imag(p[i]) > std::imag(p[is])) is = i;
    if (std::imag(p[i]) < std::imag(p[js])) js = i;
  }
  Real maxdis = std::norm(p[is] - p[js]);

  int maxi, maxj, i, j;
  i = maxi = is;
  j = maxj = js;
  do {
    if (cross(p[(i + 1) % N] - p[i], p[(j + 1) % N] - p[j]) >= 0) {
      j = (j + 1) % N;
    } else {
      i = (i + 1) % N;
    }
    if (std::norm(p[i] - p[j]) > maxdis) {
      maxdis = std::norm(p[i] - p[j]);
      maxi = i;
      maxj = j;
    }
  } while (i != is || j != js);
  return std::minmax(maxi, maxj);
}
}  // namespace geometry
#line 11 "test/verify/aoj-cgl-4-b.test.cpp"

using namespace std;
using namespace geometry;

int main() {
  cout << fixed << setprecision(10);
  int N;
  cin >> N;
  Polygon p(N);
  for (int i = 0; i < N; i++) {
    cin >> p[i];
  }
  auto ret = convex_polygon_diameter(p);
  cout << abs(p[ret.first] - p[ret.second]) << "\n";
}

Test cases

Env	Name	Status	Elapsed	Memory
g++	00_sample_00	AC	3 ms	4 MB
g++	00_sample_01	AC	2 ms	4 MB
g++	00_sample_02	AC	2 ms	4 MB
g++	01_small_00	AC	2 ms	4 MB
g++	01_small_01	AC	2 ms	4 MB
g++	01_small_02	AC	2 ms	4 MB
g++	01_small_03	AC	2 ms	4 MB
g++	01_small_04	AC	2 ms	4 MB
g++	03_rand_00	AC	2 ms	4 MB
g++	03_rand_01	AC	2 ms	4 MB
g++	03_rand_02	AC	2 ms	4 MB
g++	03_rand_03	AC	2 ms	4 MB
g++	03_rand_04	AC	2 ms	4 MB
g++	03_rand_05	AC	2 ms	4 MB
g++	03_rand_06	AC	2 ms	4 MB
g++	04_radial_00	AC	3 ms	4 MB
g++	04_radial_01	AC	4 ms	4 MB
g++	05_maximum_00	AC	11 ms	4 MB
g++	05_maximum_01	AC	11 ms	4 MB
g++	06_linear_00	AC	3 ms	4 MB
g++	06_linear_01	AC	12 ms	4 MB
g++	06_linear_02	AC	6 ms	4 MB
g++	06_linear_03	AC	69 ms	5 MB
g++	06_linear_04	AC	25 ms	4 MB
clang++	00_sample_00	AC	3 ms	4 MB
clang++	00_sample_01	AC	2 ms	4 MB
clang++	00_sample_02	AC	2 ms	4 MB
clang++	01_small_00	AC	2 ms	4 MB
clang++	01_small_01	AC	2 ms	4 MB
clang++	01_small_02	AC	2 ms	4 MB
clang++	01_small_03	AC	2 ms	4 MB
clang++	01_small_04	AC	2 ms	4 MB
clang++	03_rand_00	AC	2 ms	4 MB
clang++	03_rand_01	AC	2 ms	4 MB
clang++	03_rand_02	AC	2 ms	4 MB
clang++	03_rand_03	AC	2 ms	4 MB
clang++	03_rand_04	AC	2 ms	4 MB
clang++	03_rand_05	AC	2 ms	4 MB
clang++	03_rand_06	AC	2 ms	4 MB
clang++	04_radial_00	AC	3 ms	4 MB
clang++	04_radial_01	AC	4 ms	4 MB
clang++	05_maximum_00	AC	11 ms	4 MB
clang++	05_maximum_01	AC	12 ms	4 MB
clang++	06_linear_00	AC	2 ms	4 MB
clang++	06_linear_01	AC	11 ms	4 MB
clang++	06_linear_02	AC	6 ms	4 MB
clang++	06_linear_03	AC	77 ms	5 MB
clang++	06_linear_04	AC	27 ms	4 MB