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

#include <algorithm> // min, max, swap, sort, reverse, lower_bound, upper_bound
#include <bitset>    // bitset
#include <cctype>    // isupper, islower, isdigit, toupper, tolower
#include <cstdint>   // int64_t, int*_t
#include <cstdio>    // printf
#include <deque>     // deque
#include <iostream>  // cout, endl, cin
#include <map>       // map
#include <queue>     // queue, priority_queue
#include <set>       // set
#include <stack>     // stack
#include <string>    // string, to_string, stoi
#include <tuple>     // tuple, make_tuple
#include <unordered_map> // unordered_map
#include <unordered_set> // unordered_set
#include <utility>       // pair, make_pair
#include <vector>        // vector
using namespace std;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define Rep(i, s, n) for (int i = s; i < n; i++)
#define fi first
#define se second
#define all(c) c.begin(), c.end()
typedef long long int ll;
typedef pair<int, int> P;
typedef long double ld;
void Ans(bool x) {
  if (x)
    cout << "Yes" << endl;
  else
    cout << "No" << endl;
}

const ll INF = 1001001001;
const ll mod = 1000000007;

struct mint {
  ll x; // typedef long long ll;
  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(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 gcd(ll a, ll b) {
  if (a == 0 || b == 0)
    return 0;
  if (a < 0)
    return gcd((-1) * a, b);
  if (b < 0)
    return gcd(a, (-1) * b);
  if (b < a)
    return gcd(b, a);
  if (b % a == 0)
    return a;
  return gcd(b % a, a);
}

int main() {
  ll n;
  cin >> n;
  ll a, b;
  P v[n];
  vector<P> vc;
  map<P, int> mp;

  rep(i, n) {
    cin >> a >> b;
    int ch = 0;
    ll g = gcd(a, b);
    if (g == 0) {
      if (a != 0) {
        mp[P(1, 0)]++;
      } else if (b != 0) {
        mp[P(0, -1)]++;
      } else {
        mp[P(0, 0)]++;
      }
    }

    else {
      v[i] = P(a / g, b / g);
      if (mp[P(a / g, b / g)] == 0 && mp[P((-1) * a / g, (-1) * b / g)] == 0 &&
          mp[P((-1) * b / g, a / g)] == 0 && mp[P(b / g, (-1) * a / g)] == 0) {
        ch++;
      }

      if (a > 0 && b > 0) {
        mp[P(a / g, b / g)]++;
        if (ch != 0)
          vc.push_back(P(a / g, b / g));
      } else if (a < 0 && b < 0) {
        mp[P((-1) * a / g, (-1) * b / g)]++;
        if (ch != 0)
          vc.push_back(P((-1) * a / g, (-1) * b / g));
      } else if (a > 0 && b < 0) {
        mp[P(a / g, b / g)]++;
        if (ch != 0)
          vc.push_back(P(a / g, b / g));
      } else if (a < 0 && b > 0) {
        mp[P((-1) * a / g, (-1) * b / g)]++;
        if (ch != 0)
          vc.push_back(P((-1) * a / g, (-1) * b / g));
      }
    }
  }

  vc.push_back(P(1, 0));

  mint ans = 1;
  mint d = 2;
  for (auto p : vc) {
    ll j = mp[p];
    ll k = max(mp[P(p.se, (-1) * p.fi)], mp[P((-1) * p.se, p.fi)]);
    ans *= (d.pow(j) + d.pow(k) - 1);
    // cout<<j<<" "<<k<<endl;
  }
  ans -= 1;
  ans += mp[P(0, 0)];
  cout << ans.x << endl;
}


Error: 0

Fixed submission:

#include <algorithm> // min, max, swap, sort, reverse, lower_bound, upper_bound
#include <bitset>    // bitset
#include <cctype>    // isupper, islower, isdigit, toupper, tolower
#include <cstdint>   // int64_t, int*_t
#include <cstdio>    // printf
#include <deque>     // deque
#include <iostream>  // cout, endl, cin
#include <map>       // map
#include <queue>     // queue, priority_queue
#include <set>       // set
#include <stack>     // stack
#include <string>    // string, to_string, stoi
#include <tuple>     // tuple, make_tuple
#include <unordered_map> // unordered_map
#include <unordered_set> // unordered_set
#include <utility>       // pair, make_pair
#include <vector>        // vector
using namespace std;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define Rep(i, s, n) for (int i = s; i < n; i++)
#define fi first
#define se second
#define all(c) c.begin(), c.end()
typedef long long int ll;
typedef pair<int, int> P;
typedef long double ld;
void Ans(bool x) {
  if (x)
    cout << "Yes" << endl;
  else
    cout << "No" << endl;
}

const ll INF = 1001001001;
const ll mod = 1000000007;

struct mint {
  ll x; // typedef long long ll;
  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(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 gcd(ll a, ll b) {
  if (a < 0)
    return gcd((-1) * a, b);
  if (b < 0)
    return gcd(a, (-1) * b);
  if (b < a)
    return gcd(b, a);
  if (b % a == 0)
    return a;
  return gcd(b % a, a);
}

int main() {
  ll n;
  cin >> n;
  ll a, b;
  P v[n];
  vector<P> vc;
  map<P, int> mp;

  rep(i, n) {
    cin >> a >> b;
    int ch = 0;
    ll g = gcd(a, b);
    v[i] = P(a / g, b / g);
    if (mp[P(a / g, b / g)] == 0 && mp[P((-1) * a / g, (-1) * b / g)] == 0 &&
        mp[P((-1) * b / g, a / g)] == 0 && mp[P(b / g, (-1) * a / g)] == 0) {
      ch++;
    }

    if (a > 0 && b > 0) {
      mp[P(a / g, b / g)]++;
      if (ch != 0)
        vc.push_back(P(a / g, b / g));
    } else if (a < 0 && b < 0) {
      mp[P((-1) * a / g, (-1) * b / g)]++;
      if (ch != 0)
        vc.push_back(P((-1) * a / g, (-1) * b / g));
    } else if (a > 0 && b < 0) {
      mp[P(a / g, b / g)]++;
      if (ch != 0)
        vc.push_back(P(a / g, b / g));
    } else if (a < 0 && b > 0) {
      mp[P((-1) * a / g, (-1) * b / g)]++;
      if (ch != 0)
        vc.push_back(P((-1) * a / g, (-1) * b / g));
    }
  }

  mint ans = 1;
  mint d = 2;
  for (auto p : vc) {
    ll j = mp[p];
    ll k = max(mp[P(p.se, (-1) * p.fi)], mp[P((-1) * p.se, p.fi)]);
    ans *= (d.pow(j) + d.pow(k) - 1);
    // cout<<j<<" "<<k<<endl;
  }
  ans -= 1;
  cout << ans.x << endl;
}