Cod sursa(job #3215575)
Utilizator | Draghici Paul Paul281881818818181991919191881818 | Data | 15 martie 2024 10:14:25 |
---|---|---|---|
Problema | Aria | Scor | 70 |
Compilator | cpp-64 | Status | done |
Runda | Arhiva educationala | Marime | 0.55 kb |
#include <fstream>
#include <iomanip>
std::ifstream fin("aria.in");
std::ofstream fout("aria.out");
class point{
public:
double x, y;
};
point arr[100005];
int main(){
int n;
fin >> n;
for(int i = 1; i <= n; i++){
fin >> arr[i].x >> arr[i].y;
}
long double sum = 0;
arr[n + 1] = arr[1];
for(int i = 1; i <= n; i ++){
sum += ((arr[i].x * arr[i + 1].y) - (arr[i + 1].x * arr[i].y));
}
if(sum < 0)
sum = -sum;
fout << std::fixed << std::setprecision(5) << sum / 2.0;
}