Cod sursa(job #2800952)
Utilizator | Burac Vlad vladburac | Data | 14 noiembrie 2021 16:00:17 |
---|---|---|---|
Problema | Aria | Scor | 0 |
Compilator | cpp-64 | Status | done |
Runda | Arhiva educationala | Marime | 0.46 kb |
#include <iostream>
#include <fstream>
#include <iomanip>
using namespace std;
const int NMAX = 1e5;
ifstream fin( "aria.in" );
ofstream fout( "aria.out" );
double x[NMAX+1];
double y[NMAX+1];
int main() {
int n, i;
double s = 0;
cin >> n;
for( i = 0; i < n; i++ )
cin >> x[i] >> y[i];
x[n] = x[0];
y[n] = y[0];
for( i = 0; i < n; i++ )
s += x[i] * y[i+1] - x[i+1] * y[i];
cout << setprecision(5) << s / 2;
return 0;
}