Cod sursa(job #2500272)

Utilizator HaiduculAndrei Popa Haiducul Data 27 noiembrie 2019 17:28:16
Problema Aria Scor 0
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 0.33 kb
Raporteaza aceasta sursa 
#include <fstream>
using namespace std;
ifstream f("aria.in");
ofstream g("aria.out");
int n;
long long a,x[1000005],y[1000005];
int main()
{   f>>n;
    for(int i=1;i<=n;i++)   f>>x[i]>>y[i];
    x[n+1]=x[1];
    y[n+1]=y[1];
    for(int i=1;i<=n;i++) a+=x[i]*y[i+1]-x[i+1]*y[i];
    if(a<0) a=-a;
    g<<a/2;
    return 0;
}