Cod sursa(job #2773347)
Utilizator | Data | 6 septembrie 2021 17:25:42 | |
---|---|---|---|
Problema | Aria | Scor | 60 |
Compilator | cpp-64 | Status | done |
Runda | Arhiva educationala | Marime | 0.42 kb |
#include <bits/stdc++.h>
#include <iomanip>
using namespace std;
ifstream fin ("aria.in");
ofstream fout("aria.out");
struct ceva
{
double x,y;
}v[100010];
int n,i;
double ans;
int main()
{
fin>>n;
for(i=1;i<=n;i++)
fin>>v[i].x>>v[i].y;
v[n+1]=v[1];
for(i=1;i<=n;i++)
ans=ans+(v[i].x*v[i+1].y)-(v[i+1].x*v[i].y);
fout<<fixed<<setprecision(5)<<fabs(ans/2);
return 0;
}