Language: C++

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

const ll MOD = 1000000007LL;

ll mymod(ll a){
    if(a<0){
        a = -a;
        a %= MOD;
        return (MOD - a)%MOD;
    }
    return a%MOD;
}

ll mysho(ll a){
    
    if(a%MOD==0)
        return a/MOD;
    else if(a<0){
        a = -a;
        a /= MOD;
        return -a-1;
    }
    return a/MOD;
}


int main(){
    
    ll n; cin >>n;
    
    vector<ll> a(n), b(n);
    
    for(int i=0; i<n; i++){
        cin >> a[i] >> b[i];
    }
    
    double c;
    
    vector<tuple<double, ll, ll>> data;
    
    for(int i=0; i<n; i++){
        tuple<double, ll, ll> t((double)(atan2(b[i],a[i])/(M_PI/2))-(int)((double)(atan2(b[i],a[i])/(M_PI/2))) , a[i], b[i]);
        data.push_back(t);
    }
    
    sort(data.begin(), data.end());
    
    ll count = 0;
    
    for(int i=0; i<n; i++){
        int j=i+1;
        while(j<n && get<0>(data[i])==get<0>(data[j])){
            vector<ll> pai(3), pbi(3), paj(3), pbj(3);
            pai[0] = mymod(get<1>(data[i]));
            pai[1] = mysho(get<1>(data[i]));
            pbi[0] = mymod(get<2>(data[i]));
            pbi[1] = mysho(get<2>(data[i]));
            paj[0] = mymod(get<1>(data[j]));
            paj[1] = mysho(get<1>(data[j]));
            pbj[0] = mymod(get<2>(data[j]));
            pbj[1] = mysho(get<2>(data[j]));
            ll prod(4);
            for(int k=0; k<2; k++){
                for(int l=0; l<2; l++){
                    prod[i+j] += pai[k] * paj[l];
                    prod[i+j] += pbi[k] * pbj[l];
                }
            }
            for(int k=0; k<3; k++){
                prod[k+1] += mysho(prod[k]);
                prod[k] = mymod(prod[k]);
            }
            if(!prod[0] &&!prod[1] &&!prod[2] &&!prod[3])
                count ++;
        }
    }
    
    cout << ((n*(n-1)/2)%MOD + (MOD-count)%MOD)%MOD << endl;
    
    return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:67:25: error: invalid types 'll {aka long long int}[int]' for array subscript
   67 |                     prod[i+j] += pai[k] * paj[l];
      |                         ^
a.cc:68:25: error: invalid types 'll {aka long long int}[int]' for array subscript
   68 |                     prod[i+j] += pbi[k] * pbj[l];
      |                         ^
a.cc:72:21: error: invalid types 'll {aka long long int}[int]' for array subscript
   72 |                 prod[k+1] += mysho(prod[k]);
      |                     ^
a.cc:72:40: error: invalid types 'll {aka long long int}[int]' for array subscript
   72 |                 prod[k+1] += mysho(prod[k]);
      |                                        ^
a.cc:73:21: error: invalid types 'll {aka long long int}[int]' for array subscript
   73 |                 prod[k] = mymod(prod[k]);
      |                     ^
a.cc:73:37: error: invalid types 'll {aka long long int}[int]' for array subscript
   73 |                 prod[k] = mymod(prod[k]);
      |                                     ^
a.cc:75:21: error: invalid types 'll {aka long long int}[int]' for array subscript
   75 |             if(!prod[0] &&!prod[1] &&!prod[2] &&!prod[3])
      |                     ^
a.cc:75:32: error: invalid types 'll {aka long long int}[int]' for array subscript
   75 |             if(!prod[0] &&!prod[1] &&!prod[2] &&!prod[3])
      |                                ^
a.cc:75:43: error: invalid types 'll {aka long long int}[int]' for array subscript
   75 |             if(!prod[0] &&!prod[1] &&!prod[2] &&!prod[3])
      |                                           ^
a.cc:75:54: error: invalid types 'll {aka long long int}[int]' for array subscript
   75 |             if(!prod[0] &&!prod[1] &&!prod[2] &&!prod[3])
      |                                                      ^