Cod sursa(job #2839727)
Utilizator | Furtuna-Cola Andrei Alexandru KitsuRaine | Data | 26 ianuarie 2022 14:45:06 |
---|---|---|---|
Problema | Aria | Scor | 100 |
Compilator | cpp-64 | Status | done |
Runda | Arhiva educationala | Marime | 0.41 kb |
#include <fstream>
#include <iomanip>
using namespace std;
ifstream f("aria.in");
ofstream g("aria.out");
int n,i;
long double I[100001],J[100001],s;
int main()
{
f>>n;
for(i=1;i<=n;i++)
{
f>>I[i]>>J[i];
}
I[n+1]=I[1];
J[n+1]=J[1];
for(i=1;i<=n;i++)
s=s+(I[i]*J[i+1])-(I[i+1]*J[i]);
s=s/(2.0);
g<<fixed<<setprecision(6)<<s;
return 0;
}