Cod sursa(job #1177216)
Utilizator | Banu Denis Andrei DenisONIc | Data | 26 aprilie 2014 11:59:55 |
---|---|---|---|
Problema | Aria | Scor | 70 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.45 kb |
#include <fstream>
#include <iomanip>
using namespace std;
ifstream f("aria.in");
ofstream g("aria.out");
long n,i,j;
double s;
struct ab{
double x,y;
};
ab v[100001];
int main()
{
f>>n;
for (i=1;i<=n;i++)
f>>v[i].x>>v[i].y;
for (i=1;i<=n-1;i++)
s+=(v[i].x*v[i+1].y-v[i+1].x*v[i].y)/2;
s+=(v[n].x*v[1].y-v[1].x*v[n].y)/2;
g.precision(10);
g<<s;
f.close();
g.close();
return 0;
}