Cod sursa(job #1827895)
Utilizator | Adia R. adiaioana | Data | 12 decembrie 2016 14:37:41 |
---|---|---|---|
Problema | Aria | Scor | 0 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.45 kb |
#include <fstream>
#include <iomanip>
using namespace std;
ifstream fin("aria.in");
ofstream fout("aria.out");
double ar;
struct point{
int x,y;
}p[100001];
int main()
{
int n,i;
fin>>n;
for(i=1;i<=n;i++)
fin>>p[i].x>>p[i].y;
p[n+1]=p[1];
ar=0;
for(i=1;i<=n;i++)
ar+=((p[i].y+p[i+1].y)*(p[i+1].x-p[i].x));
if(ar<0) ar=-ar;
ar=ar/2;
fout.precision(6);
fout<<fixed<<ar;
return 0;
}