library

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:heavy_check_mark: test/aoj/CGL_1_B.test.cpp

Depends on

Code

#define PROBLEM "http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=CGL_1_B"
#define ERROR "0.00000001"
#include "../../geometry/template.hpp"

#include <iostream>
using namespace std;
int main() {
  Line l; cin >> l;
  int q; cin >> q;
  for (int i = 0; i < q; ++i) {
    Point p; cin >> p;
    Point x = reflection(l, p);
    cout << x << endl;
  }
}
#line 1 "test/aoj/CGL_1_B.test.cpp"
#define PROBLEM "http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=CGL_1_B"
#define ERROR "0.00000001"
#line 2 "geometry/template.hpp"
#include <cmath>
#include <algorithm>
#include <complex>
#include <functional>
#include <iomanip>
#include <iostream>
#include <vector>
using namespace std;

using Real = double;
using Point = complex< Real >;
const Real EPS = 1e-10, PI = acos(-1);
#define X real()
#define Y imag()

inline bool eq(Real a, Real b) { return fabs(b - a) < EPS; }

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

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

ostream &operator<<(ostream &os, Point &p) {
  return os << fixed << setprecision(10) << p.X << " " << p.Y;
}

// rotate point p counterclockwise by theta rad
Point rotate(Real theta, const Point &p) {
  return Point(cos(theta) * p.X - sin(theta) * p.Y, sin(theta) * p.X + cos(theta) * p.Y);
}

Real radian_to_degree(Real r) {
  return (r * 180.0 / PI);
}

Real degree_to_radian(Real d) {
  return (d * PI / 180.0);
}

// smaller angle of the a-b-c
Real get_angle(const Point &a, const Point &b, const Point &c) {
  const Point v(b - a), w(c - b);
  Real alpha = atan2(v.Y, v.X), beta = atan2(w.Y, w.X);
  if(alpha > beta) swap(alpha, beta);
  Real theta = (beta - alpha);
  return min(theta, 2 * acos(-1) - theta);
}

namespace std {
  bool operator<(const Point &a, const Point &b) {
    return a.X != b.X ? a.X < b.X : a.Y < b.Y;
  }
}


struct Line {
  Point a, b;

  Line() = default;

  Line(Point a, Point b) : a(a), b(b) {}

  Line(Real A, Real B, Real C) // Ax + By = C
  {
    if(eq(A, 0)) a = Point(0, C / B), b = Point(1, C / B);
    else if(eq(B, 0)) b = Point(C / A, 0), b = Point(C / A, 1);
    else a = Point(0, C / B), b = Point(C / A, 0);
  }

  friend ostream &operator<<(ostream &os, Line &p) {
    return os << p.a << " to " << p.b;
  }

  friend istream &operator>>(istream &is, Line &a) {
    return is >> a.a >> a.b;
  }
};

struct Segment : Line {
  Segment() = default;

  Segment(Point a, Point b) : Line(a, b) {}
};

using Points = vector< Point >;
using Polygon = vector< Point >;
using Segments = vector< Segment >;
using Lines = vector< Line >;

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);
}

// http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=CGL_1_C
int ccw(const Point &a, const Point &b, const Point &c) {
  Point b2 = b-a;
  Point c2 = c-a;
  if(cross(b2, c2) > EPS) return +1;  // "COUNTER_CLOCKWISE"
  if(cross(b2, c2) < -EPS) return -1; // "CLOCKWISE"
  if(dot(b2, c2) < 0) return +2;      // "ONLINE_BACK" c-a-b
  if(norm(b2) < norm(c2)) return -2;  // "ONLINE_FRONT" a-b-c
  return 0;                         // "ON_SEGMENT" a-c-b
}

// http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=CGL_2_A
bool parallel(const Line &a, const Line &b) {
  return eq(cross(a.b - a.a, b.b - b.a), 0.0);
}

// http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=CGL_2_A
bool orthogonal(const Line &a, const Line &b) {
  return eq(dot(a.a - a.b, b.a - b.b), 0.0);
}

// http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=CGL_1_A
Point projection(const Line &l, const Point &p) {
  double t = dot(p - l.a, l.a - l.b) / norm(l.a - l.b);
  return l.a + (l.a - l.b) * t;
}

Point projection(const Segment &l, const Point &p) {
  double t = dot(p - l.a, l.a - l.b) / norm(l.a - l.b);
  return l.a + (l.a - l.b) * t;
}

// http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=CGL_1_B
Point reflection(const Line &l, const Point &p) {
  return p + (projection(l, p) - p) * 2.0;
}

bool intersect(const Line &l, const Point &p) {
  return abs(ccw(l.a, l.b, p)) != 1;
}

bool intersect(const Line &l, const Line &m) {
  return abs(cross(l.b - l.a, m.b - m.a)) > EPS || abs(cross(l.b - l.a, m.b - l.a)) < EPS;
}

bool intersect(const Segment &s, const Point &p) {
  return ccw(s.a, s.b, p) == 0;
}

bool intersect(const Line &l, const Segment &s) {
  return cross(l.b - l.a, s.a - l.a) * cross(l.b - l.a, s.b - l.a) < EPS;
}

Real distance(const Line &l, const Point &p);

// http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=CGL_2_B
bool intersect(const Segment &s, const Segment &t) {
  return ccw(s.a, s.b, t.a) * ccw(s.a, s.b, t.b) <= 0 && ccw(t.a, t.b, s.a) * ccw(t.a, t.b, s.b) <= 0;
}

Real distance(const Point &a, const Point &b) {
  return abs(a - b);
}

Real distance(const Line &l, const Point &p) {
  return abs(p - projection(l, p));
}

Real distance(const Line &l, const Line &m) {
  return intersect(l, m) ? 0 : distance(l, m.a);
}

Real distance(const Segment &s, const Point &p) {
  Point r = projection(s, p);
  if(intersect(s, r)) return abs(r - p);
  return min(abs(s.a - p), abs(s.b - p));
}

// http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=CGL_2_D
Real distance(const Segment &a, const Segment &b) {
  if(intersect(a, b)) return 0;
  return min({distance(a, b.a), distance(a, b.b), distance(b, a.a), distance(b, a.b)});
}

Real distance(const Line &l, const Segment &s) {
  if(intersect(l, s)) return 0;
  return min(distance(l, s.a), distance(l, s.b));
}

Point crosspoint(const Line &l, const Line &m) {
  Real A = cross(l.b - l.a, m.b - m.a);
  Real B = cross(l.b - l.a, l.b - m.a);
  if(eq(abs(A), 0.0) && eq(abs(B), 0.0)) return m.a;
  return m.a + (m.b - m.a) * B / A;
}

// http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=CGL_2_C
Point crosspoint(const Segment &l, const Segment &m) {
  return crosspoint(Line(l), Line(m));
}

// http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=CGL_3_B
bool is_convex(const Polygon &p) {
  int n = (int) p.size();
  for(int i = 0; i < n; i++) {
    if(ccw(p[(i + n - 1) % n], p[i], p[(i + 1) % n]) == -1) return false;
  }
  return true;
}

// http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=CGL_4_A
Polygon convex_hull(Polygon &p) {
  int n = (int) p.size(), k = 0;
  if(n <= 2) return p;
  sort(p.begin(), p.end());
  vector< Point > ch(2 * n);
  for(int i = 0; i < n; ch[k++] = p[i++]) {
    while(k >= 2 && cross(ch[k - 1] - ch[k - 2], p[i] - ch[k - 1]) < EPS) --k;
  }
  for(int i = n - 2, t = k + 1; i >= 0; ch[k++] = p[i--]) {
    while(k >= t && cross(ch[k - 1] - ch[k - 2], p[i] - ch[k - 1]) < EPS) --k;
  }
  ch.resize(k - 1);
  return ch;
}

// http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=CGL_3_C
enum {
  OUT, ON, IN
};

int contains(const Polygon &Q, const Point &p) {
  bool in = false;
  for(int i = 0; i < (int)Q.size(); i++) {
    Point a = Q[i] - p, b = Q[(i + 1) % Q.size()] - p;
    if(a.Y > b.Y) swap(a, b);
    if(a.Y <= 0 && 0 < b.Y && cross(a, b) < 0) in = !in;
    if(cross(a, b) == 0 && dot(a, b) <= 0) return ON;
  }
  return in ? IN : OUT;
}


// http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=1033
// deduplication of line segments
void merge_segments(vector< Segment > &segs) {

  auto merge_if_able = [](Segment &s1, const Segment &s2) {
    if(abs(cross(s1.b - s1.a, s2.b - s2.a)) > EPS) return false;
    if(ccw(s1.a, s2.a, s1.b) == 1 || ccw(s1.a, s2.a, s1.b) == -1) return false;
    if(ccw(s1.a, s1.b, s2.a) == -2 || ccw(s2.a, s2.b, s1.a) == -2) return false;
    s1 = Segment(min(s1.a, s2.a), max(s1.b, s2.b));
    return true;
  };

  for(int i = 0; i < (int)segs.size(); i++) {
    if(segs[i].b < segs[i].a) swap(segs[i].a, segs[i].b);
  }
  for(int i = 0; i < (int)segs.size(); i++) {
    for(int j = i + 1; j < (int)segs.size(); j++) {
      if(merge_if_able(segs[i], segs[j])) {
        segs[j--] = segs.back(), segs.pop_back();
      }
    }
  }
}

// http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=1033
// construct a graph with the vertex of the intersection of any two line segments
vector< vector< int > > segment_arrangement(vector< Segment > &segs, vector< Point > &ps) {
  vector< vector< int > > g;
  int N = (int) segs.size();
  for(int i = 0; i < N; i++) {
    ps.emplace_back(segs[i].a);
    ps.emplace_back(segs[i].b);
    for(int j = i + 1; j < N; j++) {
      const Point p1 = segs[i].b - segs[i].a;
      const Point p2 = segs[j].b - segs[j].a;
      if(cross(p1, p2) == 0) continue;
      if(intersect(segs[i], segs[j])) {
        ps.emplace_back(crosspoint(segs[i], segs[j]));
      }
    }
  }
  sort(begin(ps), end(ps));
  ps.erase(unique(begin(ps), end(ps)), end(ps));

  int M = (int) ps.size();
  g.resize(M);
  for(int i = 0; i < N; i++) {
    vector< int > vec;
    for(int j = 0; j < M; j++) {
      if(intersect(segs[i], ps[j])) {
        vec.emplace_back(j);
      }
    }
    for(int j = 1; j < (int)vec.size(); j++) {
      g[vec[j - 1]].push_back(vec[j]);
      g[vec[j]].push_back(vec[j - 1]);
    }
  }
  return (g);
}

// http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=CGL_4_C
// cut with a straight line l and return a convex polygon on the left
Polygon convex_cut(const Polygon &U, Line l) {
  Polygon ret;
  for(int i = 0; i < (int)U.size(); i++) {
    Point now = U[i], nxt = U[(i + 1) % U.size()];
    if(ccw(l.a, l.b, now) != -1) ret.push_back(now);
    if(ccw(l.a, l.b, now) * ccw(l.a, l.b, nxt) < 0) {
      ret.push_back(crosspoint(Line(now, nxt), l));
    }
  }
  return (ret);
}

// http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=CGL_3_A
Real area(const Polygon &p) {
  Real A = 0;
  for(int i = 0; i < (int)p.size(); ++i) {
    A += cross(p[i], p[(i + 1) % p.size()]);
  }
  return A * 0.5;
}

// http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=CGL_4_B
Real convex_diameter(const Polygon &p) {
  int N = (int) p.size();
  int is = 0, js = 0;
  for(int i = 1; i < N; i++) {
    if(p[i].Y > p[is].Y) is = i;
    if(p[i].Y < p[js].Y) js = i;
  }
  Real maxdis = 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(norm(p[i] - p[j]) > maxdis) {
      maxdis = norm(p[i] - p[j]);
      maxi = i;
      maxj = j;
    }
  } while(i != is || j != js);
  return sqrt(maxdis);
}

// http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=CGL_5_A
Real closest_pair(Points ps) {
  if(ps.size() <= 1) throw (0);
  sort(begin(ps), end(ps));

  auto compare_y = [&](const Point &a, const Point &b) {
    return imag(a) < imag(b);
  };
  vector< Point > beet(ps.size());
  const Real INF = 1e18;

  function< Real(int, int) > rec = [&](int left, int right) {
    if(right - left <= 1) return INF;
    int mid = (left + right) >> 1;
    auto x = real(ps[mid]);
    auto ret = min(rec(left, mid), rec(mid, right));
    inplace_merge(begin(ps) + left, begin(ps) + mid, begin(ps) + right, compare_y);
    int ptr = 0;
    for(int i = left; i < right; i++) {
      if(abs(real(ps[i]) - x) >= ret) continue;
      for(int j = 0; j < ptr; j++) {
        auto luz = ps[i] - beet[ptr - j - 1];
        if(imag(luz) >= ret) break;
        ret = min(ret, abs(luz));
      }
      beet[ptr++] = ps[i];
    }
    return ret;
  };
  return rec(0, (int) ps.size());
}
#line 4 "test/aoj/CGL_1_B.test.cpp"

#line 6 "test/aoj/CGL_1_B.test.cpp"
using namespace std;
int main() {
  Line l; cin >> l;
  int q; cin >> q;
  for (int i = 0; i < q; ++i) {
    Point p; cin >> p;
    Point x = reflection(l, p);
    cout << x << endl;
  }
}
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