Problem p02304 (C++) — buggy submission, verdict: Time Limit Exceeded

#include <bits/stdc++.h>
using namespace std;

#define pb(n) push_back(n)
#define fi first
#define se second
#define all(r) begin(r), end(r)
#define vmax(ary) *max_element(all(ary))
#define vmin(ary) *min_element(all(ary))
#define debug(x) cout << #x << ": " << x << endl
#define fcout(n) cout << fixed << setprecision((n))
#define scout(n) cout << setw(n)
#define vary(type, name, size, init) vector<type> name(size, init)
#define vvl(v, w, h, init) vector<vector<ll>> v(w, vector<ll>(h, init))
#define mp(a, b) make_pair(a, b)

#define rep(i, n) for (int i = 0; i < (int)(n); ++i)
#define REP(i, a, b) for (int i = (a); i < (int)(b); ++i)
#define repi(it, array)                                                        \\
  for (auto it = array.begin(), end = array.end(); it != end; ++it)
#define repa(n, array) for (auto &n : (array))

using ll = long long;
using pii = pair<int, int>;
using pll = pair<ll, ll>;

template <typename T> void O(T t) { cout << t << endl; }

const ll mod = 1e9 + 7;
constexpr ll inf = ((1 << 30) - 1) * 2 + 1;
const double EPS = 1e-8;
const double INF = 1e12;
typedef complex<double> P; //????´???°????????¢?????????????????¨?§£???
namespace std {
bool operator<(const P &a, const P &b) { // x????????????
  return real(a) != real(b) ? real(a) < real(b) : imag(a) < imag(b);
}
bool sorty(const P &a, const P &b) { // y????????????
  return imag(a) != imag(b) ? imag(a) < imag(b) : real(a) < real(b);
}
bool same(const P &a, const P &b) {
  P p = a - b;
  if (abs(real(p)) < EPS && abs(imag(p)) < EPS) {
    return true;
  }
  return false;
}
} // namespace std
double cross(const P &a, const P &b) { //??????
  return imag(conj(a) * b);
}
double dot(const P &a, const P &b) { //??????
  return real(conj(a) * b);
}

struct L : public vector<P> { //??´???
  L(){};
  L(const P &a, const P &b) {
    push_back(a);
    push_back(b);
  }
};

typedef vector<P> G;

struct C { //???
  P p;
  double r;
  C(){};
  C(const P &p, double r) : p(p), r(r) {}
};
int ccw(P a, P b, P c) { // 3????????????????????§????????§??????????????????
  b -= a;
  c -= a;
  if (cross(b, c) > 0)
    return +1; // counter clockwise
  if (cross(b, c) < 0)
    return -1; // clockwise
  if (dot(b, c) < 0)
    return +2; // c--a--b on line
  if (norm(b) < norm(c))
    return -2; // a--b--c on line
  return 0;    // a--c--b on line
}
int linejudge(const L &ab, const L &cd) { // 2??´???????????¢???
  P a = ab[1] - ab[0], b = cd[1] - cd[0];
  if (abs(cross(a, b)) < EPS) { // Parallel
    return 2;
  } else if (abs(dot(a, b)) < EPS) { // Orthogonal
    return 1;
  }
  return 0;
}
// L:line,S:segment,P:point
bool intersectLL(const L &l, const L &m) {
  return abs(cross(l[1] - l[0], m[1] - m[0])) > EPS || // non-parallel
         abs(cross(l[1] - l[0], m[0] - l[0])) < EPS;   // same line
}
bool intersectLS(const L &l, const L &s) {
  return cross(l[1] - l[0], s[0] - l[0]) * // s[0] is left of l
             cross(l[1] - l[0], s[1] - l[0]) <
         EPS; // s[1] is right of l
}
bool intersectLP(const L &l, const P &p) {
  return abs(cross(l[1] - p, l[0] - p)) < EPS;
}
bool intersectSS(const L &s, const L &t) {
  return ccw(s[0], s[1], t[0]) * ccw(s[0], s[1], t[1]) <= 0 &&
         ccw(t[0], t[1], s[0]) * ccw(t[0], t[1], s[1]) <= 0;
}
bool intersectSP(const L &s, const P &p) {
  return abs(s[0] - p) + abs(s[1] - p) - abs(s[1] - s[0]) <
         EPS; // triangle inequality
}
// L & P intersection
P projection(const L &l, const P &p) {
  double t = dot(p - l[0], l[0] - l[1]) / norm(l[0] - l[1]);
  return l[0] + t * (l[0] - l[1]);
}
// L????????????P???????°????
P reflection(const L &l, const P &p) {
  return p + 2.0 * (projection(l, p) - p);
}
double distanceLP(const L &l, const P &p) { return abs(p - projection(l, p)); }
double distanceLL(const L &l, const L &m) {
  return intersectLL(l, m) ? 0 : distanceLP(l, m[0]);
}
double distanceLS(const L &l, const L &s) {
  if (intersectLS(l, s))
    return 0;
  return min(distanceLP(l, s[0]), distanceLP(l, s[1]));
}
double distanceSP(const L &s, const P &p) {
  const P r = projection(s, p);
  if (intersectSP(s, r))
    return abs(r - p);
  return min(abs(s[0] - p), abs(s[1] - p));
}
double distanceSS(const L &s, const L &t) {
  if (intersectSS(s, t))
    return 0;
  return min(min(distanceSP(s, t[0]), distanceSP(s, t[1])),
             min(distanceSP(t, s[0]), distanceSP(t, s[1])));
}
double distancePP(const P &p, const P &q) { return abs(p - q); }
P crosspoint(const L &l, const L &m) {
  double A = cross(l[1] - l[0], m[1] - m[0]);
  double B = cross(l[1] - l[0], l[1] - m[0]);
  if (abs(A) < EPS && abs(B) < EPS)
    return m[0]; // same line
  if (abs(A) < EPS)
    assert(false); // !!!PRECONDITION NOT SATISFIED!!!
  return m[0] + B / A * (m[1] - m[0]);
}
P verticalvector(const P &a,
                 const P &b) { // 2???????????????????????????????????????
  if (a.real() == b.real()) {
    return {1.0, 0};
  }
  if (a.imag() == b.imag()) {
    return {0, 1.0};
  }
  P p = a - b;
  P res = {-p.imag(), p.real()};
  return res / abs(p);
}
pair<P, P> crosspointCircle(const C &a, const C &b) {
  P m = (a.p + b.p) / 2.0;
  P vv = verticalvector(a.p, b.p);
  double u = sqrt(a.r * a.r - norm(a.p - b.p) / 4.0);
  P A = m + u * vv, B = m - u * vv;
  return mp(A, B);
}
double calc_triangle(P a, P b, P c) {
  P ba = (b - a);
  P ca = (c - a);
  return (real(ba) * imag(ca) - imag(ba) * real(ca)) / 2.0;
}
double calc_area(const G &g) {
  double res = 0;
  rep(i, g.size() - 2) {
    res += calc_triangle(g[0], g[(i + 1) % g.size()], g[(i + 2) % g.size()]);
  }
  return res;
}
bool is_convex(const G &g) {
  if (g.size() == 3)
    return true;
  rep(i, g.size()) {
    if (ccw(g[i], g[(i + 1) % g.size()], g[(i + 2) % g.size()]) != 1 &&
        ccw(g[i], g[(i + 1) % g.size()], g[(i + 2) % g.size()]) != -2) {
      return false;
    }
  }
  return true;
}
int convex_point(const G &g, const P &p) {
  P q = p - P(-INF, imag(p));
  double x = real(p), y = imag(p);
  L l1(p, q);
  ll cn = 0;
  rep(i, g.size()) {
    P a = g[i], b = g[(i + 1) % g.size()];
    L l2 = L(a, b);
    int k = ccw(a, b, p);
    if (k == 0) {
      return 1; // p on g
    }
  }
  rep(i, g.size()) {
    P a = g[i], b = g[(i + 1) % g.size()];
    double y1 = imag(a), y2 = imag(b);
    if (!(y1 == y && y2 == y) && ((y1 <= y && y < y2) || (y2 <= y && y < y1))) {
      L l2 = L(a, b);
      P c = crosspoint(l1, l2);
      if (x < real(c))
        ++cn;
    }
  }
  if (cn % 2)
    return 2; // p in g
  return 0;   // p out g
}
vector<P> convex_hull(vector<P> &ps) {
  sort(all(ps));
  int k = 0;
  int n = ps.size();
  vector<P> qs(ps.size() * 2);
  rep(i, ps.size()) {
    while (k > 1 && cross((qs[k - 1] - qs[k - 2]), (ps[i] - qs[k - 1])) < 0) {
      k--;
    }
    qs[k++] = ps[i];
  }
  for (int i = n - 2, t = k; i >= 0; i--) {
    while (k > t && cross((qs[k - 1] - qs[k - 2]), (ps[i] - qs[k - 1])) < 0) {
      k--;
    }
    qs[k++] = ps[i];
  }
  qs.resize(k - 1);
  return qs;
}
#define curr(P, i) P[i]
#define next(P, i) P[(i + 1) % P.size()]
#define diff(P, i) (next(P, i) - curr(P, i))
double convex_diameter(vector<P> &ps) {
  const int n = ps.size();
  int is = 0, js = 0;
  REP(i, 1, n) {
    if (imag(ps[i]) > imag(ps[is]))
      is = i;
    if (imag(ps[i]) < imag(ps[js]))
      js = i;
  }
  double d = norm(ps[is] - ps[js]);
  int im, jm, i, j;
  i = im = is;
  j = jm = js;
  do {
    if (cross(diff(ps, i), diff(ps, j)) >= 0)
      j = (j + 1) % n;
    else
      i = (i + 1) % n;
    if (norm(ps[i] - ps[j]) > d) {
      d = norm(ps[i] - ps[j]);
      im = i, jm = j;
    }
  } while (i != is || j != js);
  return sqrt(d);
}
G convex_cut(G &g, L &l) {
  G h;
  rep(i, (int)g.size()) {
    P p = curr(g, i), q = next(g, i);
    if (ccw(p, q, l[0]) == 0 && ccw(p, q, l[1]) == 0) {
      if (ccw(p, l[1], l[0]) == 0)
        return g; // p -- l.a -- l.b -- q
      else
        return G{}; // p -- l.b -- l.a -- q
    }
    if (ccw(l[0], l[1], p) != -1)
      h.emplace_back(p);
    if (ccw(l[0], l[1], p) * ccw(l[0], l[1], q) < 0)
      h.emplace_back(crosspoint(L(p, q), l));
  }
  return h;
}
double closestPair_calc(P *p, int n) {
  if (n < 2)
    return inf;
  int m = n / 2;
  double x = real(p[m]);
  double d = min(closestPair_calc(p, m), closestPair_calc(p + m, n - m));
  inplace_merge(p, p + m, p + n, sorty);
  vector<P> q;
  double dx, dy;
  rep(i, n) {
    if (abs(real(p[i]) - x) >= d)
      continue;

    for (int j = q.size() - 1; j >= 0; j--) {
      dx = real(p[i]) - real(q[j]);
      dy = imag(p[i]) - imag(q[j]);
      if (dy >= d)
        break;
      d = min(d, sqrt(dx * dx + dy * dy));
    }
    q.push_back(p[i]);
  }
  return d;
}
double closestPair(vector<P> &p, int n) {
  if (n < 2)
    return 0.0;
  sort(all(p));
  double ans = closestPair_calc(&p[0], n);
  return ans == inf ? 0.0 : ans;
}
P unit(const L &l) {
  P p = l[1] - l[0];
  return p / abs(p);
}
P unit(const P &a, const P &b) {
  P p = b - a;
  return p / abs(p);
}
int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  ll n;
  cin >> n;
  vector<L> lx, ly;
  double x, y;
  L xp = L(P(0, 0), P(1, 0));
  L yp = L(P(0, 0), P(0, 1));
  rep(i, n) {
    cin >> x >> y;
    P a(x, y);
    cin >> x >> y;
    P b(x, y);
    if (b < a)
      swap(a, b);
    L l(a, b);
    if (linejudge(l, xp) == 2) {
      lx.emplace_back(l);
    } else {
      ly.emplace_back(l);
    }
  }
  sort(all(lx));
  sort(all(ly));
  ll cnt = 0;
  rep(i, lx.size()) {
    int l = 0, r = ly.size(), tl, tr;
    double x1 = real(lx[i][0]), x2 = real(lx[i][1]);
    rep(j, 100) {
      int m = (l + r) / 2;
      if (real(ly[m][0]) < x1) {
        l = m;
      } else {
        r = m;
      }
    }
    tl = l;
    l = 0, r = ly.size();
    rep(j, 100) {
      int m = (l + r) / 2;
      if (real(ly[m][0]) > x2) {
        r = m;
      } else {
        l = m;
      }
    }
    tr = r;
    /* cout << endl;                                          */
    /* std::cout << lx[i][0] << ' ' << lx[i][1] << std::endl; */
    /* cout << endl;                                          */
    REP(j, tl, tr) {
      /* std::cout << ly[j][0] << ' ' << ly[j][1]; */
      if (intersectSS(lx[i], ly[j])) {
        ++cnt;
        /* cout << 'o'; */
      }
      /* cout << endl; */
    }
  }
  cout << cnt << endl;
  return 0;
}

Error: TLE

Fixed submission:

#include <bits/stdc++.h>
using namespace std;

#define pb(n) push_back(n)
#define fi first
#define se second
#define all(r) begin(r), end(r)
#define vmax(ary) *max_element(all(ary))
#define vmin(ary) *min_element(all(ary))
#define debug(x) cout << #x << ": " << x << endl
#define fcout(n) cout << fixed << setprecision((n))
#define scout(n) cout << setw(n)
#define vary(type, name, size, init) vector<type> name(size, init)
#define vvl(v, w, h, init) vector<vector<ll>> v(w, vector<ll>(h, init))
#define mp(a, b) make_pair(a, b)

#define rep(i, n) for (int i = 0; i < (int)(n); ++i)
#define REP(i, a, b) for (int i = (a); i < (int)(b); ++i)
#define repi(it, array)                                                        \\
  for (auto it = array.begin(), end = array.end(); it != end; ++it)
#define repa(n, array) for (auto &n : (array))

using ll = long long;
using pii = pair<int, int>;
using pll = pair<ll, ll>;

template <typename T> void O(T t) { cout << t << endl; }

const ll mod = 1e9 + 7;
constexpr ll inf = ((1 << 30) - 1) * 2 + 1;
const double EPS = 1e-8;
const double INF = 1e12;
typedef complex<double> P; //????´???°????????¢?????????????????¨?§£???
namespace std {
bool operator<(const P &a, const P &b) { // x????????????
  return real(a) != real(b) ? real(a) < real(b) : imag(a) < imag(b);
}
bool sorty(const P &a, const P &b) { // y????????????
  return imag(a) != imag(b) ? imag(a) < imag(b) : real(a) < real(b);
}
bool same(const P &a, const P &b) {
  P p = a - b;
  if (abs(real(p)) < EPS && abs(imag(p)) < EPS) {
    return true;
  }
  return false;
}
} // namespace std
double cross(const P &a, const P &b) { //??????
  return imag(conj(a) * b);
}
double dot(const P &a, const P &b) { //??????
  return real(conj(a) * b);
}

struct L : public vector<P> { //??´???
  L(){};
  L(const P &a, const P &b) {
    push_back(a);
    push_back(b);
  }
};

typedef vector<P> G;

struct C { //???
  P p;
  double r;
  C(){};
  C(const P &p, double r) : p(p), r(r) {}
};
int ccw(P a, P b, P c) { // 3????????????????????§????????§??????????????????
  b -= a;
  c -= a;
  if (cross(b, c) > 0)
    return +1; // counter clockwise
  if (cross(b, c) < 0)
    return -1; // clockwise
  if (dot(b, c) < 0)
    return +2; // c--a--b on line
  if (norm(b) < norm(c))
    return -2; // a--b--c on line
  return 0;    // a--c--b on line
}
int linejudge(const L &ab, const L &cd) { // 2??´???????????¢???
  P a = ab[1] - ab[0], b = cd[1] - cd[0];
  if (abs(cross(a, b)) < EPS) { // Parallel
    return 2;
  } else if (abs(dot(a, b)) < EPS) { // Orthogonal
    return 1;
  }
  return 0;
}
// L:line,S:segment,P:point
bool intersectLL(const L &l, const L &m) {
  return abs(cross(l[1] - l[0], m[1] - m[0])) > EPS || // non-parallel
         abs(cross(l[1] - l[0], m[0] - l[0])) < EPS;   // same line
}
bool intersectLS(const L &l, const L &s) {
  return cross(l[1] - l[0], s[0] - l[0]) * // s[0] is left of l
             cross(l[1] - l[0], s[1] - l[0]) <
         EPS; // s[1] is right of l
}
bool intersectLP(const L &l, const P &p) {
  return abs(cross(l[1] - p, l[0] - p)) < EPS;
}
bool intersectSS(const L &s, const L &t) {
  return ccw(s[0], s[1], t[0]) * ccw(s[0], s[1], t[1]) <= 0 &&
         ccw(t[0], t[1], s[0]) * ccw(t[0], t[1], s[1]) <= 0;
}
bool intersectSP(const L &s, const P &p) {
  return abs(s[0] - p) + abs(s[1] - p) - abs(s[1] - s[0]) <
         EPS; // triangle inequality
}
// L & P intersection
P projection(const L &l, const P &p) {
  double t = dot(p - l[0], l[0] - l[1]) / norm(l[0] - l[1]);
  return l[0] + t * (l[0] - l[1]);
}
// L????????????P???????°????
P reflection(const L &l, const P &p) {
  return p + 2.0 * (projection(l, p) - p);
}
double distanceLP(const L &l, const P &p) { return abs(p - projection(l, p)); }
double distanceLL(const L &l, const L &m) {
  return intersectLL(l, m) ? 0 : distanceLP(l, m[0]);
}
double distanceLS(const L &l, const L &s) {
  if (intersectLS(l, s))
    return 0;
  return min(distanceLP(l, s[0]), distanceLP(l, s[1]));
}
double distanceSP(const L &s, const P &p) {
  const P r = projection(s, p);
  if (intersectSP(s, r))
    return abs(r - p);
  return min(abs(s[0] - p), abs(s[1] - p));
}
double distanceSS(const L &s, const L &t) {
  if (intersectSS(s, t))
    return 0;
  return min(min(distanceSP(s, t[0]), distanceSP(s, t[1])),
             min(distanceSP(t, s[0]), distanceSP(t, s[1])));
}
double distancePP(const P &p, const P &q) { return abs(p - q); }
P crosspoint(const L &l, const L &m) {
  double A = cross(l[1] - l[0], m[1] - m[0]);
  double B = cross(l[1] - l[0], l[1] - m[0]);
  if (abs(A) < EPS && abs(B) < EPS)
    return m[0]; // same line
  if (abs(A) < EPS)
    assert(false); // !!!PRECONDITION NOT SATISFIED!!!
  return m[0] + B / A * (m[1] - m[0]);
}
P verticalvector(const P &a,
                 const P &b) { // 2???????????????????????????????????????
  if (a.real() == b.real()) {
    return {1.0, 0};
  }
  if (a.imag() == b.imag()) {
    return {0, 1.0};
  }
  P p = a - b;
  P res = {-p.imag(), p.real()};
  return res / abs(p);
}
pair<P, P> crosspointCircle(const C &a, const C &b) {
  P m = (a.p + b.p) / 2.0;
  P vv = verticalvector(a.p, b.p);
  double u = sqrt(a.r * a.r - norm(a.p - b.p) / 4.0);
  P A = m + u * vv, B = m - u * vv;
  return mp(A, B);
}
double calc_triangle(P a, P b, P c) {
  P ba = (b - a);
  P ca = (c - a);
  return (real(ba) * imag(ca) - imag(ba) * real(ca)) / 2.0;
}
double calc_area(const G &g) {
  double res = 0;
  rep(i, g.size() - 2) {
    res += calc_triangle(g[0], g[(i + 1) % g.size()], g[(i + 2) % g.size()]);
  }
  return res;
}
bool is_convex(const G &g) {
  if (g.size() == 3)
    return true;
  rep(i, g.size()) {
    if (ccw(g[i], g[(i + 1) % g.size()], g[(i + 2) % g.size()]) != 1 &&
        ccw(g[i], g[(i + 1) % g.size()], g[(i + 2) % g.size()]) != -2) {
      return false;
    }
  }
  return true;
}
int convex_point(const G &g, const P &p) {
  P q = p - P(-INF, imag(p));
  double x = real(p), y = imag(p);
  L l1(p, q);
  ll cn = 0;
  rep(i, g.size()) {
    P a = g[i], b = g[(i + 1) % g.size()];
    L l2 = L(a, b);
    int k = ccw(a, b, p);
    if (k == 0) {
      return 1; // p on g
    }
  }
  rep(i, g.size()) {
    P a = g[i], b = g[(i + 1) % g.size()];
    double y1 = imag(a), y2 = imag(b);
    if (!(y1 == y && y2 == y) && ((y1 <= y && y < y2) || (y2 <= y && y < y1))) {
      L l2 = L(a, b);
      P c = crosspoint(l1, l2);
      if (x < real(c))
        ++cn;
    }
  }
  if (cn % 2)
    return 2; // p in g
  return 0;   // p out g
}
vector<P> convex_hull(vector<P> &ps) {
  sort(all(ps));
  int k = 0;
  int n = ps.size();
  vector<P> qs(ps.size() * 2);
  rep(i, ps.size()) {
    while (k > 1 && cross((qs[k - 1] - qs[k - 2]), (ps[i] - qs[k - 1])) < 0) {
      k--;
    }
    qs[k++] = ps[i];
  }
  for (int i = n - 2, t = k; i >= 0; i--) {
    while (k > t && cross((qs[k - 1] - qs[k - 2]), (ps[i] - qs[k - 1])) < 0) {
      k--;
    }
    qs[k++] = ps[i];
  }
  qs.resize(k - 1);
  return qs;
}
#define curr(P, i) P[i]
#define next(P, i) P[(i + 1) % P.size()]
#define diff(P, i) (next(P, i) - curr(P, i))
double convex_diameter(vector<P> &ps) {
  const int n = ps.size();
  int is = 0, js = 0;
  REP(i, 1, n) {
    if (imag(ps[i]) > imag(ps[is]))
      is = i;
    if (imag(ps[i]) < imag(ps[js]))
      js = i;
  }
  double d = norm(ps[is] - ps[js]);
  int im, jm, i, j;
  i = im = is;
  j = jm = js;
  do {
    if (cross(diff(ps, i), diff(ps, j)) >= 0)
      j = (j + 1) % n;
    else
      i = (i + 1) % n;
    if (norm(ps[i] - ps[j]) > d) {
      d = norm(ps[i] - ps[j]);
      im = i, jm = j;
    }
  } while (i != is || j != js);
  return sqrt(d);
}
G convex_cut(G &g, L &l) {
  G h;
  rep(i, (int)g.size()) {
    P p = curr(g, i), q = next(g, i);
    if (ccw(p, q, l[0]) == 0 && ccw(p, q, l[1]) == 0) {
      if (ccw(p, l[1], l[0]) == 0)
        return g; // p -- l.a -- l.b -- q
      else
        return G{}; // p -- l.b -- l.a -- q
    }
    if (ccw(l[0], l[1], p) != -1)
      h.emplace_back(p);
    if (ccw(l[0], l[1], p) * ccw(l[0], l[1], q) < 0)
      h.emplace_back(crosspoint(L(p, q), l));
  }
  return h;
}
double closestPair_calc(P *p, int n) {
  if (n < 2)
    return inf;
  int m = n / 2;
  double x = real(p[m]);
  double d = min(closestPair_calc(p, m), closestPair_calc(p + m, n - m));
  inplace_merge(p, p + m, p + n, sorty);
  vector<P> q;
  double dx, dy;
  rep(i, n) {
    if (abs(real(p[i]) - x) >= d)
      continue;

    for (int j = q.size() - 1; j >= 0; j--) {
      dx = real(p[i]) - real(q[j]);
      dy = imag(p[i]) - imag(q[j]);
      if (dy >= d)
        break;
      d = min(d, sqrt(dx * dx + dy * dy));
    }
    q.push_back(p[i]);
  }
  return d;
}
double closestPair(vector<P> &p, int n) {
  if (n < 2)
    return 0.0;
  sort(all(p));
  double ans = closestPair_calc(&p[0], n);
  return ans == inf ? 0.0 : ans;
}
P unit(const L &l) {
  P p = l[1] - l[0];
  return p / abs(p);
}
P unit(const P &a, const P &b) {
  P p = b - a;
  return p / abs(p);
}
int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  ll n;
  cin >> n;
  vector<L> lx, ly;
  double x, y;
  L xp = L(P(0, 0), P(1, 0));
  L yp = L(P(0, 0), P(0, 1));
  rep(i, n) {
    cin >> x >> y;
    P a(x, y);
    cin >> x >> y;
    P b(x, y);
    L l(a, b);
    if (linejudge(l, xp) == 2) {
      lx.emplace_back(l);
    } else {
      ly.emplace_back(l);
    }
  }
  ll cnt = 0;
  rep(i, lx.size()) {
    rep(j, ly.size()) {
      if (intersectSS(lx[i], ly[j])) {
        ++cnt;
      }
    }
  }
  cout << cnt << endl;
  return 0;
}