Cod sursa(job #1398130)

Utilizator zpaePopescu Andreea zpae Data 24 martie 2015 00:17:23
Problema Aria Scor 0
Compilator cpp Status done
Runda Arhiva educationala Marime 0.34 kb
Raporteaza aceasta sursa 
#include <fstream>

using namespace std;

int main()
{
    ifstream in ("aria.in");
    ofstream out ("aria.out");
    int r=0,n,x,y,a,b,xx,yy;
    in>>n>>x>>y;
    xx=x;
    yy=y;
    while(--n)
    {
        in>>a>>b;
        r+=(x*b-a*y);
        x=a;
        y=b;
    }
    r+=(xx*b-a*yy);
    out<<r<<"\n";
    return 0;
}