Cod sursa(job #2700568)

Utilizator BogdanTicuTicu Bogdan Valeriu BogdanTicu Data 28 ianuarie 2021 02:50:04
Problema Aria Scor 70
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 0.37 kb
#include <bits/stdc++.h>

using namespace std;

ifstream in("aria.in");
ofstream out("aria.out");

pair<double,double> v[100005];
int main()
{
	int n;
	in>>n;
	for(int i=1;i<=n;i++)
		in>>v[i].first>>v[i].second;
	v[n+1]=v[1];
	double s=0;
	for(int i=1;i<=n;i++)
		s+=(v[i].first*v[i+1].second-v[i+1].first*v[i].second);
	out<<setprecision(6)<<fixed<<s / 2.0<<"\n";
	return 0;
}