Cod sursa(job #2371784)
Utilizator | Data | 6 martie 2019 19:37:58 | |
---|---|---|---|
Problema | Aria | Scor | 0 |
Compilator | cpp-64 | Status | done |
Runda | Arhiva educationala | Marime | 0.49 kb |
#include <bits/stdc++.h>
using namespace std;
ifstream in("aria.in");
ofstream out("aria.out");
int n;
double long ans = 0;
struct cell
{
int x, y;
}c[100010];
int main()
{
in >> n;
for(int i = 1;i <= n;i++)
in >> c[i].x >> c[i].y;
c[n + 1].x = c[1].x;
c[n + 1].y = c[1].y;
for(int i = 1;i <= n;i++)
ans = ans + (1.0 * (1.0 * c[i].x * c[i + 1].y - 1.0 * c[i + 1].x * c[i].y)) / 2.0;
out << setprecision(5) << ans;
return 0;
}