Cod sursa(job #1017352)
Utilizator | Ilie Mihai octiocti | Data | 27 octombrie 2013 18:19:07 |
---|---|---|---|
Problema | Aria | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.43 kb |
# include <cstdio>
# include <cmath>
using namespace std;
int n,i;
double sol;
struct punct
{
double x,y;
}a[100005];
int main()
{
freopen("aria.in","r",stdin);
freopen("aria.out","w",stdout);
scanf("%d",&n);
for(i=0;i<n;++i)
scanf("%lf%lf",&a[i].x,&a[i].y);
a[n]=a[0];
for(i=0;i<n;++i)
sol+=a[i].x*a[i+1].y-a[i+1].x*a[i].y;
printf("%lf\n",fabs(sol/2.0));
return 0;
}