Cod sursa(job #2559496)
Utilizator | Sirbu Radu-Mihai radumihaisirbu | Data | 27 februarie 2020 12:46:25 |
---|---|---|---|
Problema | Aria | Scor | 0 |
Compilator | cpp-64 | Status | done |
Runda | Arhiva educationala | Marime | 0.57 kb |
#include <bits/stdc++.h>
using namespace std;
ifstream fin ("aria.in");
ofstream fout ("aria.out");
#define x first
#define y second
const int nmax = 1e5 + 5;
pair <int, int> p[nmax];
double sol = .5, sum = 0;
int n;
double arie (pair <int, int> A, pair <int, int>B)
{
return A.x * B.y - A.y * B.x;
}
int main()
{
fin >> n;
for (int i=1; i<=n; ++i)
fin >> p[i].x >> p[i].y;
p[n+1] = p[1];
for (int i=2; i<=n+1; ++i)
sum += arie(p[i], p[i-1]);
sol *= sum;
fout << fabs(sol);
return 0;
}