Cod sursa(job #1973254)
Utilizator | TEST CENTRE TESTHARD123 | Data | 24 aprilie 2017 19:59:40 |
---|---|---|---|
Problema | Aria | Scor | 0 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.46 kb |
#include <fstream>
#include <algorithm>
std::ifstream in ("aria.in");
std::ofstream out ("aria.out");
struct point
{
double x,y;
};
int n;
point pts[100003];
int main()
{
in >> n;
for( int i = 0; i < n; i++)
{
double x,y;
in >> x >> y;
pts[i]=(point){x,y};
}
pts[n]=pts[0];
double ar=0;
for(int i = 0; i < n; i++)
{
ar+=(pts[i].x*pts[i+1].y-pts[i+1].x*pts[i].y)/2;
}
out.precision(6);
out.setf(ios::fixed,ios::floatfield);
out << abs(ar);
}