Cod sursa(job #2316489)
Utilizator | Moanta Ionut Liviu Liviu_Ionut_Moanta | Data | 11 ianuarie 2019 20:05:41 |
---|---|---|---|
Problema | Aria | Scor | 70 |
Compilator | cpp-64 | Status | done |
Runda | Arhiva educationala | Marime | 0.56 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++){
if(sum>=0){
sum-=(x[i+1]/2)*y[i];
sum+=(x[i]/2)*y[i+1];
}
else{
sum+=(x[i]/2)*y[i+1];
sum-=(x[i+1]/2)*y[i];
}
}
fout<<fixed<<setprecision(5)<<sum;
return 0;
}