Problem p02679 (C++) — buggy submission, verdict: Runtime Error

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

typedef long long ll;
#define int long long

#define SZ(x) ((int)(x).size())
#define ALL(x) (x).begin(), (x).end()

#define FOR(i, a, b) for (int i = (int)(a); i < (int)(b); i++)
#define REP(i, x) for (int i = 0; i < (int)(x); i++)
#define REPS(i, x) for (int i = 1; i <= (int)(x); i++)
#define RREP(i, x) for (int i = ((int)(x)-1); i >= 0; i--)
#define RREPS(i, x) for (int i = ((int)(x)); i > 0; i--)

typedef pair<int, int> pint;
typedef vector<int> vecint;

#define mp make_pair
#define mt make_tuple
#define pb push_back
#define pf push_front

#define MOD (1000L * 1000L * 1000L + 7L)

template <typename T> vector<T> readArray(int N) {
  vector<T> vec(N);

  for (auto &v : vec) {
    cin >> v;
  }

  return vec;
}

template <typename T> T read() {
  T a;
  cin >> a;
  return a;
}

int readInt() {
  int a;
  cin >> a;
  return a;
}
double readDouble() {
  double a;
  cin >> a;
  return a;
}
string readStr() {
  string a;
  cin >> a;
  return a;
}

namespace math {
long long pow_mod(long long a, long long b, long long M) {
  long ret = 1;
  long tmp = a;

  while (b > 0) {
    if ((b & 1) == 1)
      ret = (ret * tmp) % M;
    tmp = (tmp * tmp) % M;
    b = b >> 1;
  }

  return ret;
}

long long nCk(long long n, long long k, long long M) {
  long ret = 1;
  int _min = std::min(k, n - k);

  for (int i = 1; i <= _min; i++) {
    ret = (ret * pow_mod(i, M - 2, M)) % M;
  }
  for (int i = n - _min + 1; i <= n; i++) {
    ret = (ret * i) % M;
  }

  return (long long)ret;
}

long long gcd(long long a, long long b) {
  if (a < b)
    return gcd(b, a);
  if (b == 0)
    return a;
  return gcd(b, a % b);
}
} // namespace math

pair<int, int> _div(int a, int b) {
  int c = math::gcd(a < 0 ? -a : a, b < 0 ? -b : b);
  a /= c;
  b /= c;

  if (b < 0) {
    a *= -1;
    b *= -1;
  }

  return mp(a, b);
}

struct hoge {
  int cnt;
  bool check;
};

void Main() {
  int n = readInt();
  vecint a(n);
  vecint b(n);

  REP(i, n) { cin >> a[i] >> b[i]; }

  map<pint, hoge> m;
  int zeros = 0;
  REP(i, n) {
    if (a[i] == 0 && b[i] == 0) {
      zeros++;
      continue;
    }

    pint p = _div(a[i], b[i]);
    if (p.first == 0) {
      p = mp(0, 1);
    } else if (p.second == 0) {
      p = mp(-1, 0);
    }

    if (m.find(p) == m.end()) {
      m[p] = hoge({0, false});
    }
    m[p].cnt++;
  }

  int ans = 1;

  for (auto &x : m) {
    if (x.second.check)
      continue;

    pint p = x.first;
    pint q = _div(-p.second, p.first);
    int h = math::pow_mod(2, x.second.cnt, MOD);
    if (m.find(q) != m.end()) {
      auto &y = m[q];
      y.check = true;
      h += math::pow_mod(2, y.cnt, MOD);
      h--;
    }

    ans *= h;
    ans %= MOD;
  }
  ans += zeros;
  if (ans > 0) {
    ans--;
  } else {
    ans = MOD - 1;
  }
  ans %= MOD;

  cout << ans << endl;
}

signed main() {
  std::cin.tie(nullptr);
  std::ios_base::sync_with_stdio(false);
  std::cout << std::fixed << std::setprecision(15);
  Main();

  return 0;
}


Error: 0

Fixed submission:

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

typedef long long ll;
#define int long long

#define SZ(x) ((int)(x).size())
#define ALL(x) (x).begin(), (x).end()

#define FOR(i, a, b) for (int i = (int)(a); i < (int)(b); i++)
#define REP(i, x) for (int i = 0; i < (int)(x); i++)
#define REPS(i, x) for (int i = 1; i <= (int)(x); i++)
#define RREP(i, x) for (int i = ((int)(x)-1); i >= 0; i--)
#define RREPS(i, x) for (int i = ((int)(x)); i > 0; i--)

typedef pair<int, int> pint;
typedef vector<int> vecint;

#define mp make_pair
#define mt make_tuple
#define pb push_back
#define pf push_front

#define MOD (1000L * 1000L * 1000L + 7L)

template <typename T> vector<T> readArray(int N) {
  vector<T> vec(N);

  for (auto &v : vec) {
    cin >> v;
  }

  return vec;
}

template <typename T> T read() {
  T a;
  cin >> a;
  return a;
}

int readInt() {
  int a;
  cin >> a;
  return a;
}
double readDouble() {
  double a;
  cin >> a;
  return a;
}
string readStr() {
  string a;
  cin >> a;
  return a;
}

namespace math {
long long pow_mod(long long a, long long b, long long M) {
  long ret = 1;
  long tmp = a;

  while (b > 0) {
    if ((b & 1) == 1)
      ret = (ret * tmp) % M;
    tmp = (tmp * tmp) % M;
    b = b >> 1;
  }

  return ret;
}

long long nCk(long long n, long long k, long long M) {
  long ret = 1;
  int _min = std::min(k, n - k);

  for (int i = 1; i <= _min; i++) {
    ret = (ret * pow_mod(i, M - 2, M)) % M;
  }
  for (int i = n - _min + 1; i <= n; i++) {
    ret = (ret * i) % M;
  }

  return (long long)ret;
}

long long gcd(long long a, long long b) {
  if (a < b)
    return gcd(b, a);
  if (b == 0)
    return a;
  return gcd(b, a % b);
}
} // namespace math

pair<int, int> _div(int a, int b) {
  int c = math::gcd(a < 0 ? -a : a, b < 0 ? -b : b);
  a /= c;
  b /= c;

  if (b < 0) {
    a *= -1;
    b *= -1;
  }

  return mp(a, b);
}

struct hoge {
  int cnt;
  bool check;
};

void Main() {
  int n = readInt();
  vecint a(n);
  vecint b(n);

  REP(i, n) { cin >> a[i] >> b[i]; }

  map<pint, hoge> m;
  REP(i, n) {
    pint p = _div(a[i], b[i]);
    if (m.find(p) == m.end()) {
      m[p] = hoge({0, false});
    }
    m[p].cnt++;
  }

  int ans = 1;

  for (auto &x : m) {
    if (x.second.check)
      continue;

    pint p = x.first;
    pint q = _div(-p.second, p.first);
    int d = n;
    int h = math::pow_mod(2, x.second.cnt, MOD);
    if (m.find(q) != m.end()) {
      auto &y = m[q];
      y.check = true;
      h += math::pow_mod(2, y.cnt, MOD);
      h--;
    }

    ans *= h;
    ans %= MOD;
  }
  ans--;

  cout << ans << endl;
}

signed main() {
  std::cin.tie(nullptr);
  std::ios_base::sync_with_stdio(false);
  std::cout << std::fixed << std::setprecision(15);
  Main();

  return 0;
}