Cod sursa(job #2297642)
Utilizator | Moanta Ionut Liviu Liviu_Ionut_Moanta | Data | 6 decembrie 2018 10:06:28 |
---|---|---|---|
Problema | Aria | Scor | 70 |
Compilator | cpp-64 | Status | done |
Runda | Arhiva educationala | Marime | 0.42 kb |
#include<fstream>
#include<iomanip>
using namespace std;
ifstream fin("aria.in");
ofstream fout("aria.out");
int n,m,i,j;
double sum,x[100005],y[100005];
int main(){
fin>>n;
for(i=1;i<=n;i++){
fin>>x[i]>>y[i];
}
x[n+1]=x[1];
y[n+1]=y[1];
for(i=1;i<=n;i++){
sum-=(x[i+1]*y[i])/2;
sum+=(x[i]*y[i+1])/2;
}
fout<<setprecision(5)<<fixed<<sum;
return 0;
}