Cod sursa(job #2202969)
Utilizator | Vasilescu Eliza Vasilescu | Data | 10 mai 2018 16:24:05 |
---|---|---|---|
Problema | Aria | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.48 kb |
#include <fstream>
#include <algorithm>
#include <iomanip>
#include <iostream>
using namespace std;
ifstream fin("aria.in");
ofstream fout("aria.out");
double xuri[100001], yuri[100001];
int main(){
int n;
fin>>n;
for(int i=1; i<=n; i++){
fin>>xuri[i]>>yuri[i];
}
double s=0;
for(int i=1; i<n; i++){
s+=xuri[i]*yuri[i+1]-xuri[i+1]*yuri[i];
}
s+=xuri[n]*yuri[1]-xuri[1]*yuri[n];
s/=2;
fout<<fixed<<setprecision(6)<<s;
return 0;
}