Cod sursa(job #1962297)
Utilizator | Data | 11 aprilie 2017 18:06:29 | |
---|---|---|---|
Problema | Aria | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.47 kb |
#include <fstream>
#include <iomanip>
using namespace std;
ifstream fin("aria.in");
ofstream fout("aria.out");
int main()
{
int n;
double x[100005], y[100005];
double A = 0;
fin >> n;
for( int i = 0; i < n; i++)
{
fin >> x[i] >> y[i];
}
x[n] = x[0];
y[n] = y[0];
for( int i = 0; i < n; i++)
{
A = A + x[i]*y[i+1] - x[i+1]*y[i];
}
fout <<fixed << setprecision(6) << A / 2;
}