Cod sursa(job #2700568)
Utilizator | Ticu Bogdan Valeriu BogdanTicu | Data | 28 ianuarie 2021 02:50:04 |
---|---|---|---|
Problema | Aria | Scor | 70 |
Compilator | cpp-64 | Status | done |
Runda | Arhiva educationala | Marime | 0.37 kb |
#include <bits/stdc++.h>
using namespace std;
ifstream in("aria.in");
ofstream out("aria.out");
pair<double,double> v[100005];
int main()
{
int n;
in>>n;
for(int i=1;i<=n;i++)
in>>v[i].first>>v[i].second;
v[n+1]=v[1];
double s=0;
for(int i=1;i<=n;i++)
s+=(v[i].first*v[i+1].second-v[i+1].first*v[i].second);
out<<setprecision(6)<<fixed<<s / 2.0<<"\n";
return 0;
}