Cod sursa(job #2427166)
Utilizator | Data | 31 mai 2019 00:32:50 | |
---|---|---|---|
Problema | Aria | Scor | 70 |
Compilator | cpp-64 | Status | done |
Runda | Arhiva educationala | Marime | 0.48 kb |
#include <fstream>
#include <iomanip>
#define NMAX 100000
using namespace std;
struct COORD {
double x, y;
}v[NMAX + 1];
int main() {
ifstream fin("aria.in");
ofstream fout("aria.out");
int n, i;
fin>>n;
for( i = 0; i < n; i ++ )
fin>>v[i].x>>v[i].y;
long double S = 0;
for( i = 0; i < n; i ++ )
S += v[i].x * v[(i+1)%n].y - v[(i+1)%n].x * v[i].y;
S = S / 2.0;
fout<<fixed<<setprecision(6)<<S;
return 0;
}