Cod sursa(job #1935086)
Utilizator | Data | 21 martie 2017 23:45:40 | |
---|---|---|---|
Problema | Aria | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.49 kb |
#include <iostream>
#include <fstream>
#include <cmath>
#include <iomanip>
using namespace std;
ifstream fin("aria.in");
ofstream fout("aria.out");
struct p{
long double x,y;
}
v[100010];
long double ras;
int i,n;
int main()
{
fin>>n;
for(i=1;i<=n;i++)
fin>>v[i].x>>v[i].y;
v[n+1].x=v[1].x;
v[n+1].y=v[1].y;
for(i=1;i<=n;i++)
ras+=(v[i].x*v[i+1].y-v[i].y*v[i+1].x);
fout<<setprecision(200)<<fabs(ras/2.0)<<'\n';
return 0;
}