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

#include <algorithm>
#include <complex>
#include <cstdio>
#include <deque>
#include <iomanip>
#include <iostream>
#include <map>
#include <memory>
#include <numeric>
#include <queue>
#include <random>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <unordered_map>
#include <vector>

#define REP(i, m, n) for (int i = int(m); i < int(n); i++)
#define RREP(i, m, n) for (int i = int(n) - 1; i >= int(m); --i)
#define EACH(i, c) for (auto &(i) : c)
#define all(c) begin(c), end(c)
#define EXIST(s, e) ((s).find(e) != (s).end())
#define SORT(c) sort(begin(c), end(c))
#define pb emplace_back
#define MP make_pair
#define SZ(a) int((a).size())
// #define int long long

#ifdef LOCAL
#define DEBUG(s) cout << (s) << endl
#define dump(x) cerr << #x << " = " << (x) << endl
#define BR cout << endl;
#else
#define DEBUG(s)                                                               \\
  do {                                                                         \\
  } while (0)
#define dump(x)                                                                \\
  do {                                                                         \\
  } while (0)
#define BR
#endif
using namespace std;

using UI = unsigned int;
using UL = unsigned long;
using LL = long long;
using ULL = unsigned long long;
using VI = vector<int>;
using VVI = vector<VI>;
using VLL = vector<LL>;
using VVLL = vector<VLL>;
using VS = vector<string>;
using PII = pair<int, int>;
using VP = vector<PII>;
template <class T> bool chmax(T &a, const T &b) {
  if (a < b) {
    a = b;
    return 1;
  }
  return 0;
}
template <class T> bool chmin(T &a, const T &b) {
  if (b < a) {
    a = b;
    return 1;
  }
  return 0;
}

constexpr int MOD = 1'000'000'007;

long long power(long long x, long long n, long long mod = 1000000007) {
  if (n == 0)
    return 1;
  if (n % 2 == 0)
    return power(x * x % mod, n / 2, mod);
  else
    return x * power(x, n - 1, mod) % mod;
}

// auto mod int
struct mint {
  LL x;
  mint(LL x = 0) : x((x % MOD + MOD) % MOD) {}
  mint operator-() const { return mint(-x); }
  mint &operator+=(const mint a) {
    if ((x += a.x) >= MOD)
      x -= MOD;
    return *this;
  }
  mint &operator-=(const mint a) {
    if ((x += MOD - a.x) >= MOD)
      x -= MOD;
    return *this;
  }
  mint &operator*=(const mint a) {
    (x *= a.x) %= MOD;
    return *this;
  }
  mint operator+(const mint a) const {
    mint res(*this);
    return res += a;
  }
  mint operator-(const mint a) const {
    mint res(*this);
    return res -= a;
  }
  mint operator*(const mint a) const {
    mint res(*this);
    return res *= a;
  }
  mint pow(const LL &t) const {
    if (!t)
      return 1;
    mint a = pow(t >> 1);
    a *= a;
    if (t & 1)
      a *= *this;
    return a;
  }

  // for prime MOD
  mint inv() const { return pow(MOD - 2); }
  mint &operator/=(const mint a) { return (*this) *= a.inv(); }
  mint operator/(const mint a) const {
    mint res(*this);
    return res /= a;
  }
  LL operator()() const { return x; }
};
using VM = vector<mint>;
using VVM = vector<VM>;

void solve() {
  int n;
  cin >> n;
  vector<pair<LL, LL>> ps;
  LL a, b;
  REP(i, 0, n) {
    cin >> a >> b;
    if (a == 0 && b == 0)
      continue;
    ps.pb(a, b);
  }

  int only = n - ps.size();
  n = ps.size();
  if (n < 2) {
    cout << n + only << endl;
    return;
  }

  map<pair<LL, LL>, int> m;
  REP(i, 0, n) {
    if (ps[i].first != 0 && ps[i].second != 0) {
      LL g = gcd(abs(ps[i].first), abs(ps[i].second));
      ps[i].first /= g;
      ps[i].second /= g;
    }
    if (ps[i].first == 0) {
      ps[i].second = 1;
    }
    if (ps[i].second == 0) {
      ps[i].first = 1;
    }

    if (ps[i].first < 0) {
      ps[i].first *= -1;
      ps[i].second *= -1;
    }
    m[MP(ps[i].first, ps[i].second)]++;
  }
  int rem = n;
  mint ans = 1;
  for (auto p : m) {
    auto key = p.first;
    int v = p.second;

    auto nkey = MP(key.second, -key.first);
    if (nkey.first <= 0) {
      nkey.first *= -1;
      nkey.second *= -1;
    }

    if (v == 0)
      continue;
    if (m.count(nkey) == 0)
      continue;
    int ov = m[nkey];
    ans *= (power(2, v) + power(2, ov) - 1) % MOD;
    m[nkey] = 0;
    rem -= v + ov;
  }
  dump(rem);
  ans *= power(2, rem);
  ans -= 1;
  ans += only;

  dump(ans());
  cout << max(0LL, ans()) << endl;
}

signed main() {
  solve();

  return 0;
}

Error: 0

Fixed submission:

#include <algorithm>
#include <complex>
#include <cstdio>
#include <deque>
#include <iomanip>
#include <iostream>
#include <map>
#include <memory>
#include <numeric>
#include <queue>
#include <random>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <unordered_map>
#include <vector>

#define REP(i, m, n) for (int i = int(m); i < int(n); i++)
#define RREP(i, m, n) for (int i = int(n) - 1; i >= int(m); --i)
#define EACH(i, c) for (auto &(i) : c)
#define all(c) begin(c), end(c)
#define EXIST(s, e) ((s).find(e) != (s).end())
#define SORT(c) sort(begin(c), end(c))
#define pb emplace_back
#define MP make_pair
#define SZ(a) int((a).size())
// #define int long long

#ifdef LOCAL
#define DEBUG(s) cout << (s) << endl
#define dump(x) cerr << #x << " = " << (x) << endl
#define BR cout << endl;
#else
#define DEBUG(s)                                                               \\
  do {                                                                         \\
  } while (0)
#define dump(x)                                                                \\
  do {                                                                         \\
  } while (0)
#define BR
#endif
using namespace std;

using UI = unsigned int;
using UL = unsigned long;
using LL = long long;
using ULL = unsigned long long;
using VI = vector<int>;
using VVI = vector<VI>;
using VLL = vector<LL>;
using VVLL = vector<VLL>;
using VS = vector<string>;
using PII = pair<int, int>;
using VP = vector<PII>;
template <class T> bool chmax(T &a, const T &b) {
  if (a < b) {
    a = b;
    return 1;
  }
  return 0;
}
template <class T> bool chmin(T &a, const T &b) {
  if (b < a) {
    a = b;
    return 1;
  }
  return 0;
}

constexpr int MOD = 1'000'000'007;

long long power(long long x, long long n, long long mod = 1000000007) {
  if (n == 0)
    return 1;
  if (n % 2 == 0)
    return power(x * x % mod, n / 2, mod);
  else
    return x * power(x, n - 1, mod) % mod;
}

// auto mod int
struct mint {
  LL x;
  mint(LL x = 0) : x((x % MOD + MOD) % MOD) {}
  mint operator-() const { return mint(-x); }
  mint &operator+=(const mint a) {
    if ((x += a.x) >= MOD)
      x -= MOD;
    return *this;
  }
  mint &operator-=(const mint a) {
    if ((x += MOD - a.x) >= MOD)
      x -= MOD;
    return *this;
  }
  mint &operator*=(const mint a) {
    (x *= a.x) %= MOD;
    return *this;
  }
  mint operator+(const mint a) const {
    mint res(*this);
    return res += a;
  }
  mint operator-(const mint a) const {
    mint res(*this);
    return res -= a;
  }
  mint operator*(const mint a) const {
    mint res(*this);
    return res *= a;
  }
  mint pow(const LL &t) const {
    if (!t)
      return 1;
    mint a = pow(t >> 1);
    a *= a;
    if (t & 1)
      a *= *this;
    return a;
  }

  // for prime MOD
  mint inv() const { return pow(MOD - 2); }
  mint &operator/=(const mint a) { return (*this) *= a.inv(); }
  mint operator/(const mint a) const {
    mint res(*this);
    return res /= a;
  }
  LL operator()() const { return x; }
};
using VM = vector<mint>;
using VVM = vector<VM>;

void solve() {
  int n;
  cin >> n;
  vector<pair<LL, LL>> ps;
  LL a, b;
  REP(i, 0, n) {
    cin >> a >> b;
    if (a == 0 || b == 0)
      continue;
    ps.pb(a, b);
  }

  n = ps.size();
  unordered_map<double, int> m;
  REP(i, 0, n) {
    double tmp = 1;
    tmp *= ps[i].first;
    tmp /= ps[i].second;
    m[tmp]++;
  }
  int rem = n;
  mint ans = 1;
  for (auto p : m) {
    double key = p.first;
    int v = p.second;

    if (v == 0)
      continue;
    if (m.count(-1.0 / key) == 0)
      continue;
    int ov = m[-1.0 / key];
    ans *= (power(2, v) + power(2, ov) - 1) % MOD;
    m[-1.0 / key] = 0;
    rem -= v + ov;
  }
  dump(rem);
  if (ans() == 1LL && rem == 0) {
    cout << 0 << endl;
    return;
  }
  ans *= power(2, rem);
  ans -= 1;

  cout << max(0LL, ans()) << endl;
}

signed main() {
  solve();

  return 0;
}