Submission #3424841

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Source Code Expand

#include <iostream>
#include <string.h>
#include <stdio.h>
#include <map>
#include <vector>
#include <math.h>
#include <algorithm>
#include <queue>
#include <set>
#include <tuple>
using namespace std;

#define rep(i,a) for(int i=0; i<a; i++)
#define rrep(i,a) for(int i=a; i>=0; i--)
#define rep1(i,a) for(int i=1; i<=a; i++)
#define cout1(a) cout << a << endl;
#define cout2(a,b) cout << a << " " << b << endl;
#define cout3(a,b,c) cout << a << " " << b << " " << c << endl;
#define cout4(a,b,c,d) cout << a << " " << b << " " << c << " " << d << endl;
#define mem(a,n) memset( a, n, sizeof(a))
#define all(a) a.begin(),a.end()

typedef long long ll;
typedef pair<int,int> pii;
typedef vector<int> V;
typedef vector<V> VV;
typedef vector<VV> VVV;
const int INF = 1e9;
const int MOD = 1e9+7;
const ll LLINF = 1e18;
static const double pi = 3.141592653589793;

class Types_triangles{
    public:
        int n;
        vector<int> y,x;
        const double EPS = 1e-10;
        ll cnt_chokaku=0, cnt_donkaku=0, cnt_eikaku=0;
        Types_triangles(const vector<int> &ty, const vector<int> &tx, int size):y(ty),x(tx),n(size){count();}
    private:
        void count(){
            rep(i,n){
                vector<double> angle;
                rep(j,n){
                    if(j==i) continue;
                    angle.push_back(atan2(y[j] - y[i], x[j] - x[i]));
                }
                sort(all(angle));
                rep(j,n-1){
                    angle.push_back(angle[j] + M_PI*2);
                }
                rep(j,n-1){
                    cnt_chokaku += upper_bound(angle.begin(), angle.end(), angle[j] + M_PI/2.0 + EPS) - lower_bound(angle.begin(), angle.end(), angle[j] + M_PI/2.0 - EPS);
                    cnt_donkaku += lower_bound(angle.begin(), angle.end(), angle[j] + M_PI) - upper_bound(angle.begin(), angle.end(), angle[j] + M_PI/2.0 + EPS);
                }
            }
            cnt_eikaku = (ll)n * (n-1) * (n-2)/6 - cnt_chokaku - cnt_donkaku;
        }
};

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    
    int N;
    cin>>N;
    
    vector<int> Y(N), X(N);
    rep(i,N) cin>>X[i]>>Y[i];
    Types_triangles t(Y,X,N);
    cout3(t.cnt_eikaku, t.cnt_chokaku, t.cnt_donkaku);
}

Submission Info

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