Cod sursa(job #3120778)
Utilizator | Data | 8 aprilie 2023 15:13:06 | |
---|---|---|---|
Problema | Aria | Scor | 100 |
Compilator | cpp-64 | Status | done |
Runda | Arhiva educationala | Marime | 0.44 kb |
#include <fstream>
#include <cmath>
#include <iomanip>
using namespace std;
ifstream cin("aria.in");
ofstream cout("aria.out");
long long n,i;
long double x[100010],y[100010];
long double aria;
int main()
{
cin>>n;
for(i=1;i<=n;i++)
cin>>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]-y[i]*x[i+1];
cout <<fixed<<setprecision(5)<<aria/(2.0);
return 0;
}