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| #include <bits/stdc++.h>
#pragma optimization_level 3
#pragma GCC optimize("Ofast,no-stack-protector,unroll-loops,fast-math,O3")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx")
#pragma GCC optimize("Ofast")
#pragma GCC target("avx,avx2,fma")
#pragma GCC optimization ("unroll-loops")
using namespace std;
struct PairHash {
inline std::size_t operator()(const std::pair<int, int> &v) const { return v.first * 31 + v.second; }
};
#define Code ios_base::sync_with_stdio(false);
#define By ios::sync_with_stdio(0);
#define Sumfi cout.tie(NULL);
using ll = long long;
using ld = long double;
const ld PI = 3.14159265358979323846;
const ll INF = 1e18;
const ld EPS = 1e-9;
const ll MAX_N = 202020;
typedef pair<ll, ll> pll;
typedef vector<pll> vpll;
typedef array<ll,3> all3;
typedef array<ll,5> all5;
typedef vector<all3> vall3;
typedef vector<all5> vall5;
typedef vector<ll> vll;
typedef vector<vll> vvll;
typedef vector<int> vi;
typedef vector<string> vs;
typedef vector<vs> vvs;
typedef unordered_set<ll> usll;
typedef unordered_set<pll, PairHash> uspll;
typedef unordered_map<ll, ll> umll;
#define rep(i,n) for(ll i=0;i<n;i++)
#define rrep(i,m,n) for(ll i=n;i>=m;i--)
#define all(a) begin(a), end(a)
#define rall(a) rbegin(a), rend(a)
ll __gcd(ll x, ll y) { return !y ? x : __gcd(y, x % y); }
ll __lcm(ll x, ll y) { return x * y / __gcd(x,y); }
using namespace std;
ll solve(vpll& A) {
ll n = A.size();
uspll us;
rep(i,n) {
rep(j,n) {
if(i == j) continue;
ll a = A[i].first - A[j].first, b = A[i].second - A[j].second;
if(a == 0 and b) b = b > 0 ? 1 : -1;
else if(b == 0 and a) a = a > 0 ? 1 : -1;
if(a and b) {
ll g = abs(__gcd(a,b));
a /= g;
b /= g;
}
us.insert({a,b});
}
}
return us.size();
}
int main() {
Code By Sumfi
ll tc = 1;
for (ll i = 1; i <= tc; i++) {
ll n;
cin>>n;
vpll A(n);
rep(i, n) cin>>A[i].first>>A[i].second;
cout<<solve(A)<<endl;
}
return 0;
}
|
