Pravokutni

#include<bits/stdc++.h>
using namespace std;
#define all(x) x.begin(), x.end()
#define debug(...) #__VA_ARGS__ << ": " << __VA_ARGS__
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);
}
bool clock_wise(pi a, pi b)
{
    return a.x * b.y - b.x * a.y > 0ll;
}
bool check(pi a)
{
    return a < make_pair(0ll, 0ll);
}
pi points[1555];
// a ^ 2 + b ^ 2 = c ^ 2
// a ^ 2 + b ^ 2 < c ^ 2
ii dist(pi a, pi b)
{
    ii ax = a.x - b.x;
    ii ay = a.y - b.y;
    return ax * ax + ay * ay;
}
int main()
{
    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) {
        map<pi,int> m;
        vector<pi> p;
        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;
            m[z]++;
            p.push_back(z);
        }
        for (int i = 0; i < n - 1; ++i) {
            auto z = p[i];
            z = make_pair(z.y, -z.x);
            r += m[z];
        }
    }
    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: TIME LIMIT EXCEEDED