Cod sursa(job #3138854)
Utilizator | Data | 22 iunie 2023 22:05:38 | |
---|---|---|---|
Problema | Aria | Scor | 100 |
Compilator | cpp-64 | Status | done |
Runda | Arhiva educationala | Marime | 0.44 kb |
#include <iostream>
#include <fstream>
#include <iomanip>
using namespace std;
ifstream fin("aria.in");
ofstream fout("aria.out");
struct Data{
long double i, j;
}x[100005];
int main()
{ long double A=0;
int n;
fin>>n;
for(int i=0;i<n;i++)
fin>>x[i].i>>x[i].j;
x[n]=x[0];
for(int i=0;i<n;i++)
A+=(x[i].i*x[i+1].j-x[i+1].i*x[i].j);
fout<<fixed<<setprecision(6)<<A/2.0;
return 0;
}