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

#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,avx512f")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#include <algorithm>
#include <bitset>
#include <cassert>
#include <cmath>
#include <complex>
#include <functional>
#include <immintrin.h>
#include <iomanip>
#include <iostream>
#include <list>
#include <map>
#include <memory>
#include <numeric>
#include <queue>
#include <random>
#include <set>
#include <stack>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <vector>
#ifdef DEBUG
#include "./Lib/Timer.hpp"
#include "./Lib/debug_VC.hpp"
#include "./Lib/sample.hpp"
#else
#define dump(...)
#endif

/* macro */
#define FOR(i, b, e) for (ll i = (ll)(b); i < (ll)(e); ++i)
#define RFOR(i, b, e) for (ll i = (ll)(e - 1); i >= (ll)(b); --i)
#define REP(i, n) FOR(i, 0, n)
#define RREP(i, n) RFOR(i, 0, n)
#define REPC(x, c) for (const auto &x : (c))
#define REPI2(it, b, e) for (auto it = (b); it != (e); ++it)
#define REPI(it, c) REPI2(it, (c).begin(), (c).end())
#define RREPI(it, c) REPI2(it, (c).rbegin(), (c).rend())
#define REPI_ERACE2(it, b, e) for (auto it = (b); it != (e);)
#define REPI_ERACE(it, c) REPI_ERACE2(it, (c).begin(), (c).end())
#define ALL(x) (x).begin(), (x).end()
#define cauto const auto &
/* macro func */
template <class T> inline auto sort(T &t) { std::sort(ALL(t)); }
template <class T> inline auto rsort(T &t) {
  std::sort((t).rbegin(), (t).rend());
}
template <class T> inline auto unique(T &t) {
  (t).erase(unique((t).begin(), (t).end()), (t).end());
}
template <class T, class S> inline auto chmax(T &t, const S &s) {
  if (s > t) {
    t = s;
    return true;
  }
  return false;
}
template <class T, class S> inline auto chmin(T &t, const S &s) {
  if (s < t) {
    t = s;
    return true;
  }
  return false;
}
inline auto BR() { std::cout << "\\n"; }

/* type define */
using ll = long long;
using PAIR = std::pair<ll, ll>;
using VS = std::vector<std::string>;
using VL = std::vector<long long>;
using VVL = std::vector<VL>;
using VVVL = std::vector<VVL>;
using VD = std::vector<double>;
template <class T> using V = std::vector<T>;

/* using std */
using std::cout;
constexpr char endl = '\\n';
using std::bitset;
using std::cin;
using std::list;
using std::map;
using std::multimap;
using std::multiset;
using std::pair;
using std::priority_queue;
using std::queue;
using std::set;
using std::stack;
using std::string;
using std::unordered_map;
using std::unordered_multimap;
using std::unordered_multiset;
using std::unordered_set;
using std::vector;

/* Initial processing  */
struct Preprocessing {
  Preprocessing() {
    std::cin.tie(0);
    std::ios::sync_with_stdio(0);
  };
} _Preprocessing;

/* Remove the source of the bug */
signed pow(signed, signed) {
  assert(false);
  return -1;
}

/* define hash */
namespace std {
template <> class hash<std::pair<ll, ll>> {
public:
  size_t operator()(const std::pair<ll, ll> &x) const {
    return hash<ll>()(1000000000 * x.first + x.second);
  }
};
} // namespace std

/* input */
template <class T> std::istream &operator>>(std::istream &is, vector<T> &vec) {
  for (T &x : vec)
    is >> x;
  return is;
}

/* constant value */
constexpr ll MOD = 1000000007;
// constexpr ll MOD = 998244353;

//=============================================================================================

ll gcd(ll a, ll b) { return b ? gcd(b, a % b) : a; }
ll lcm(ll a, ll b) { return a / gcd(a, b) * b; }

class ModCalculator {
  const long long m_mod;
  const std::vector<long long> m_fac;
  const std::vector<long long> m_finv;

  auto constructFac(long long s) {
    std::vector<long long> fac(s);
    fac[0] = fac[1] = 1;
    for (long long i = 2; i < s; ++i) {
      fac[i] = fac[i - 1] * i;
      if (fac[i] > m_mod) {
        fac[i] %= m_mod;
      }
    }
    return fac;
  }
  auto constructInv(long long s) {
    std::vector<long long> finv(s);
    finv[s - 1] = this->pow(m_fac[s - 1], m_mod - 2);
    for (long long i = s - 2; i >= 0; --i) {
      finv[i] = finv[i + 1] * (i + 1);
      if (finv[i] > m_mod) {
        finv[i] %= m_mod;
      }
    }
    return finv;
  }

public:
  ModCalculator(long long mod = MOD, long long size = 3 * 1e6)
      : m_mod(mod), m_fac(constructFac(size)), m_finv(constructInv(size)) {}

  long long pow(long long a, long long b) const {
    long long ans = 1;
    while (b > 0) {
      if (b & 1) {
        ans *= a;
        if (ans > m_mod) {
          ans %= m_mod;
        }
      }
      b >>= 1;
      a *= a;
      if (a > m_mod) {
        a %= m_mod;
      }
    }
    return ans;
  }

  auto C(int n, int r) const {
    long long val = m_fac[n] * m_finv[r];
    if (val > m_mod) {
      val %= m_mod;
    }
    val *= m_finv[n - r];
    ;
    if (val > m_mod) {
      val %= m_mod;
    }
    return val;
  }
} calc;

signed main() {
  ll n;
  cin >> n;
  map<PAIR, ll> mp;
  REP(_, n) {
    ll a, b;
    cin >> a >> b;
    if (a == 0 || b == 0) {
      if (a == 0 && b == 0) {
        mp[PAIR{0, 0}]++;
        continue;
      }
      ((a == 0) ? b : a) = 1;
      mp[PAIR{a, b}]++;
      continue;
    }
    ll g = gcd(std::abs(a), std::abs(b));
    if (a < 0) {
      a = -a;
      b = -b;
    }
    mp[PAIR{a / g, b / g}]++;
  }
  ll zero = 0;
  auto z_it = mp.find(PAIR{0, 0});
  if (z_it != mp.end()) {
    zero = z_it->second;
    mp.erase(z_it);
  }

  ll ans = 1;
  REPI_ERACE(it, mp) {
    ll val = calc.pow(2, it->second);
    ll ta = -it->first.second, tb = it->first.first;
    if (ta < 0) {
      ta = -ta;
      tb = -tb;
    }
    auto f_it = mp.find(PAIR{ta, tb});
    if (f_it != mp.end()) {
      val += calc.pow(2, f_it->second);
      mp.erase(f_it);
      --val;
    }
    if (val >= MOD) {
      val %= MOD;
    }
    // dump(val);
    ans *= val;
    if (ans >= MOD) {
      ans %= MOD;
    }
    it = mp.erase(it);
  }
  cout << (ans - 1 + zero + MOD) % MOD << endl;
}

Error: 0

Fixed submission:

#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,avx512f")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#include <algorithm>
#include <bitset>
#include <cassert>
#include <cmath>
#include <complex>
#include <functional>
#include <immintrin.h>
#include <iomanip>
#include <iostream>
#include <list>
#include <map>
#include <memory>
#include <numeric>
#include <queue>
#include <random>
#include <set>
#include <stack>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <vector>
#ifdef DEBUG
#include "./Lib/Timer.hpp"
#include "./Lib/debug_VC.hpp"
#include "./Lib/sample.hpp"
#else
#define dump(...)
#endif

/* macro */
#define FOR(i, b, e) for (ll i = (ll)(b); i < (ll)(e); ++i)
#define RFOR(i, b, e) for (ll i = (ll)(e - 1); i >= (ll)(b); --i)
#define REP(i, n) FOR(i, 0, n)
#define RREP(i, n) RFOR(i, 0, n)
#define REPC(x, c) for (const auto &x : (c))
#define REPI2(it, b, e) for (auto it = (b); it != (e); ++it)
#define REPI(it, c) REPI2(it, (c).begin(), (c).end())
#define RREPI(it, c) REPI2(it, (c).rbegin(), (c).rend())
#define REPI_ERACE2(it, b, e) for (auto it = (b); it != (e);)
#define REPI_ERACE(it, c) REPI_ERACE2(it, (c).begin(), (c).end())
#define ALL(x) (x).begin(), (x).end()
#define cauto const auto &
/* macro func */
template <class T> inline auto sort(T &t) { std::sort(ALL(t)); }
template <class T> inline auto rsort(T &t) {
  std::sort((t).rbegin(), (t).rend());
}
template <class T> inline auto unique(T &t) {
  (t).erase(unique((t).begin(), (t).end()), (t).end());
}
template <class T, class S> inline auto chmax(T &t, const S &s) {
  if (s > t) {
    t = s;
    return true;
  }
  return false;
}
template <class T, class S> inline auto chmin(T &t, const S &s) {
  if (s < t) {
    t = s;
    return true;
  }
  return false;
}
inline auto BR() { std::cout << "\\n"; }

/* type define */
using ll = long long;
using PAIR = std::pair<ll, ll>;
using VS = std::vector<std::string>;
using VL = std::vector<long long>;
using VVL = std::vector<VL>;
using VVVL = std::vector<VVL>;
using VD = std::vector<double>;
template <class T> using V = std::vector<T>;

/* using std */
using std::cout;
constexpr char endl = '\\n';
using std::bitset;
using std::cin;
using std::list;
using std::map;
using std::multimap;
using std::multiset;
using std::pair;
using std::priority_queue;
using std::queue;
using std::set;
using std::stack;
using std::string;
using std::unordered_map;
using std::unordered_multimap;
using std::unordered_multiset;
using std::unordered_set;
using std::vector;

/* Initial processing  */
struct Preprocessing {
  Preprocessing() {
    std::cin.tie(0);
    std::ios::sync_with_stdio(0);
  };
} _Preprocessing;

/* Remove the source of the bug */
const signed pow(signed, signed) {
  assert(false);
  return -1;
}

/* define hash */
namespace std {
template <> class hash<std::pair<ll, ll>> {
public:
  size_t operator()(const std::pair<ll, ll> &x) const {
    return hash<ll>()(1000000000 * x.first + x.second);
  }
};
} // namespace std

/* input */
template <class T> std::istream &operator>>(std::istream &is, vector<T> &vec) {
  for (T &x : vec)
    is >> x;
  return is;
}

/* constant value */
constexpr ll MOD = 1000000007;
// constexpr ll MOD = 998244353;

//=============================================================================================

ll gcd(ll a, ll b) { return b ? gcd(b, a % b) : a; }
ll lcm(ll a, ll b) { return a / gcd(a, b) * b; }

signed main() {
  ll n;
  cin >> n;
  map<PAIR, ll> mp;
  REP(_, n) {
    ll a, b;
    cin >> a >> b;
    ll g = gcd(std::abs(a), std::abs(b));
    if (a < 0) {
      a = -a;
      b = -b;
    }
    mp[PAIR{a / g, b / g}]++;
  }

  ll ans = 1;
  REPI_ERACE(it, mp) {
    ll val = it->second + 1;
    ll ta = -it->first.second, tb = it->first.first;
    if (ta < 0) {
      ta = -ta;
      tb = -tb;
    }
    auto f_it = mp.find(PAIR{ta, tb});
    if (f_it != mp.end()) {
      val *= (f_it->second + 1);
      mp.erase(f_it);
      --val;
    }
    if (val >= MOD) {
      val %= MOD;
    }
    // dump(val);
    ans *= val;
    if (ans >= MOD) {
      ans -= MOD;
    }
    it = mp.erase(it);
  }
  cout << (ans - 1 + MOD) % MOD << endl;
}