Cod sursa(job #1801749)
Utilizator | Data | 9 noiembrie 2016 16:37:58 | |
---|---|---|---|
Problema | Aria | Scor | 10 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.48 kb |
#include <iostream>
#include <fstream>
#include <cmath>
using namespace std;
long double num[100001][2];
int main() {
ifstream fin("aria.in");
ofstream fout("aria.out");
int n;
fin >> n;
for (int i = 0; i < n; i++)
fin >> num[i][0] >> num[i][1];
num[n][0] = num[0][0];
num[n][1] = num[0][1];
long double suma = 0;
for (int i = 0; i < n; i++)
suma += num[i][0] * num[i + 1][1] - num[i + 1][0] * num[i][1];
fout << fabs(suma / 2.0) << endl;
}