Pravokutni

#pragma GCC optimize("O3")
#include<bits/stdc++.h>
using namespace std;
#define all(x) x.begin(), x.end()
using ii=long long;
using pi=pair<ii,ii>;
#define x first
#define y second
pi operator-(pi a, pi b)
{
    return make_pair(a.x - b.x, a.y - b.y);
}
pi points[1555];
int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    int n;
    cin >> n;
    for (int i = 0; i < n; ++i) {
        cin >> points[i].x >> points[i].y;
    }
    int r = 0;
    for (int it = 0; it < n; ++it) {
        vector<pi> p, v;
        for (int j = 0; j < n; ++j) {
            if (it == j) continue;
            pi z = points[it]-points[j];
            ii u = abs(__gcd(z.x, z.y));
            z.x /= u;
            z.y /= u;
            p.emplace_back(z.y, -z.x);
            v.push_back(z);
        }
        sort(all(v));
        vector<int>occ;
        for (int i = 0; i < n - 1; ++i) {
            int j = i + 1;
            while (v[i] == v[j]) ++j;
            occ.push_back(j - i);
            i = j - 1;
        }
        v.resize(unique(all(v)) - v.begin());
        sort(all(p));
        vector<int>oc1;
        for (int i = 0; i < n - 1; ++i) {
            int j = i + 1;
            while (p[i] == p[j]) ++j;
            oc1.push_back(j - i);
            i = j - 1;
        }
        p.resize(unique(all(p)) - p.begin());
        int j = 0;
        for (int i = 0; i < (int) v.size(); ++i) {
            while (j < (int) p.size() && p[j] < v[i]) {
                j++;
            }
            if (v[i] == p[j]) {
                r += oc1[j] * occ[i];
            }
        }
    }
    cout << r << "\n";
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: TIME LIMIT EXCEEDED

Test 10

Verdict: ACCEPTED