59 lines
1.0 KiB
C++
59 lines
1.0 KiB
C++
#include <bits/stdc++.h>
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using namespace std;
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typedef long long ll;
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set<pair<ll, ll>> spells;
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ll gcd(ll a, ll b){
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if(b == 0){
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return a;
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}
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return gcd(b, a % b);
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}
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int main(){
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ios::sync_with_stdio(0);
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cin.tie(0);
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int n;
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cin >> n;
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vector<pair<ll, ll>> cities(n);
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for(int i = 0; i < n; ++i){
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ll x, y;
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cin >> x >> y;
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cities[i] = {x, y};
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for(int j = 0; j < i; ++j){
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ll dx = cities[j].first - cities[i].first;
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ll dy = cities[j].second - cities[i].second;
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if(dx == 0){
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spells.insert({0, 1});
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spells.insert({0,-1});
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} else if(dy == 0){
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spells.insert({1,0});
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spells.insert({-1, 0});
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} else{
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ll g = gcd(dx, dy);
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dx /= g;
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dy /= g;
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spells.insert({dx, dy});
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spells.insert({-1*dx, -1*dy});
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}
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}
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}
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cout << spells.size();
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cout << flush;
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return 0;
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} |