Language: C++

#include <bits/stdc++.h>
using namespace std;
typedef long long lint;
typedef vector<lint> vlint;

#define inf 1e+9
#define endl "\n"
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define rep1(i, n) for (int i = 1; i < (int)(n); i++)
#define rep_rev(i, n) for (int i = n-1; i >= 0; --i)
#define all(x) (x).begin(), (x).end()

#define pb push_back
#define eb emplace_back
#define Size(c) (int)(c).size()

#define lb(c, x) distance((c).begin(), lower_bound(all(c), (x)))
#define ub(c, x) distance((c).begin(), upper_bound(all(c), (x)))

template <class T> using pq = priority_queue<T>;
template <class T> using pqg = priority_queue<T, vector<T>, greater<T>>;

template <class T, class S> inline bool chmax(T &a, S b) {
    if(a < b) {a = b;return 1;} return 0;
}
template <class T, class S> inline bool chmin(T &a, S b) {
    if(a > b) {a = b;return 1;} return 0;
}
template <class T>
void line(vector<T> &x){for (auto&& xi : x) cin >> xi;}

inline void IN(void){ return;}

template <typename First, typename... Rest>
void IN(First& first, Rest&... rest){ cin >> first; IN(rest...); return;}

#define INT(...) int __VA_ARGS__; IN (__VA_ARGS__)
#define LINT(...) lint __VA_ARGS__; IN (__VA_ARGS__)
#define STR(...) string __VA_ARGS__; IN(__VA_ARGS__)

template <class T> void UNIQUE(vector<T> &x) {
    sort(all(x)); x.erase(unique(all(x)), x.end());
}
template <class T> void print_vec(T first, T end){
    for (auto i = first; i < end - 1; i++) cout << *i << " ";
    cout << *(end-1) << endl;
}

template<class... T>
void debug_print(T... args){
    vector<lint> tmp = initializer_list<lint>{args...};
    print_vec(all(tmp));
}
template<class T>
void print(T a){ cout << a << endl;}

vector<string> Yes = {"No", "Yes"};
vector<string> YES = {"NO", "YES"};

int ord(char x){ return (int)(x - 'a');}
char chr(lint x){ return (char)(x + (lint)('a'));}
lint mod = 1e9+7;
// lint mod = 

lint sum(vlint a){lint ret = 0; for(auto&& v:a) ret += v; return ret;}
lint vmini(vlint a, lint &index){
    lint ret = LLONG_MAX;
    rep(i, Size(a)){ if (chmin(ret, a[i])) index = i;}
    return ret;
}
lint vmaxi(vlint a, lint &index){
    lint ret = -LLONG_MAX;
    rep(i, Size(a)){ if (chmax(ret, a[i])) index = i;}
    return ret;
}

lint vmin(vlint a){
    lint ret = LLONG_MAX; for (auto && v : a) chmin(ret, v); return ret;
}
lint vmax(vlint a){
    lint ret = -LLONG_MAX; for (auto && v : a) chmax(ret, v); return ret;
}

void convert(vlint &x){
  if (x[0] == 0 && x[1] == 0) return;
  if (x[0] == 0){
    x[1] = 1; return;
  }
  if (x[1] == 0){
    x[0] = 1; return;
  }
  lint y = __gcd(x[0], x[1]);
  x[0] /= y;
  x[1] /= y;
  if (x[1] < 0){
    x[0] *= -1; x[1] *= -1;
  }
}

int main(){
    LINT(n);
    vector<vlint> ab(n, vlint(2));
    rep(i, n) cin >> ab[i][0] >> ab[i][1];
    lint mod = 1e9+7;
    vlint Ex2(n+1, 1);
    rep(i, n){
      Ex2[i+1] = Ex2[i] * 2 % mod;
    }
    map<lint, map<lint, lint>> fish;
    map<lint, map<lint, lint>> count;
    for (auto&& p : ab){
      convert(p);
      fish[p[0]][p[1]] ++;
    }
    lint x = 0;
    vector<vlint> check;
    for (auto&& [a, w] : fish){
      for (auto&& [b, cnt] : w){
        if (cnt == 0) continue;
        if (a == 0 && b == 0){
          ans++;
        }
        else if ((a == 0 || b == 0) && count[b][a] == 0){
          check.pb({cnt, fish[b][a]});
          count[b][a] = 1;
        }
        else if (a < 0 && count[b][-a] == 0){
          check.pb({cnt, fish[b][-a]});
          count[b][-a] = 1;
        }
        else if (count[-b][a] == 0){
          check.pb({cnt, fish[-b][a]});
          count[-b][a] = 1;
        }
        count[a][b] = 1;
      }
    }
    lint ans = 1; 
    for (auto&& v : check){
      ans *= ((Ex2[v[0]] - 1) + (Ex2[v[1]] - 1) + 1)%mod;
      ans %= mod;
    }
    ans += x - 1; if (ans < 0) ans += mod;
    print(ans);
}


Compiler output:
a.cc: In function 'int main()':
a.cc:121:11: error: 'ans' was not declared in this scope; did you mean 'abs'?
  121 |           ans++;
      |           ^~~
      |           abs