Pravokutni

input/code.cpp: In function 'int main()':
input/code.cpp:20:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d", &n);
     ~~~~~^~~~~~~~~~
input/code.cpp:22:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%lld%lld", &points[i].x, &points[i].y);
         ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

#pragma GCC optimize("O3")
#pragma GCC target("arch=sandybridge")
#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;
    scanf("%d", &n);
    for (int i = 0; i < n; ++i) {
        scanf("%lld%lld", &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.push_back(z);
            v.push_back(z);
        }
        sort(all(v));
        for (int i = 0; i < n - 1; ++i) {
            int t = i;
            while (t + 1 < n - 1 && p[t + 1] == p[t]) ++t;
            pi z = make_pair(p[i].y, -p[i].x);
            auto it = equal_range(all(v), z);
            if (*it.x != z) continue;
            r += (it.y - it.x) * (t - i + 1);
            i = t;
        }
    }
    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