Cod sursa(job #1015096)
Utilizator | Data | 23 octombrie 2013 21:28:11 | |
---|---|---|---|
Problema | Aria | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.44 kb |
#include <fstream>
#include <iomanip>
using namespace std;
ifstream f("aria.in");
ofstream g("aria.out");
double x[100005], y[100005];
double aria;
int n, i;
int main()
{
f>>n;
for(i=1;i<=n;i++)
f>>x[i]>>y[i];
x[n+1]=x[1];
y[n+1]=y[1];
for(i=1;i<=n;i++)
aria+=(x[i]*y[i+1]-x[i+1]*y[i]);
aria=aria/2;
if(aria<0)
aria=(-1)*aria;
g<<fixed<<setprecision(5)<<aria;
return 0;
}