Cod sursa(job #2302104)

Utilizator BlaugranasEnal Gemaledin Blaugranas Data 13 decembrie 2018 19:59:11
Problema Aria Scor 70
Compilator c-64 Status done
Runda Arhiva educationala Marime 0.33 kb
Raporteaza aceasta sursa 
#include<stdio.h>
int n,i;
double x[100002],y[100002];
long double s;
int main()
{
    freopen("aria.in","r",stdin),freopen("aria.out","w",stdout),scanf("%d",&n);
    for(i=0;i<n;i++)
        scanf("%lf%lf",x+i,y+i);
    for(x[n]=x[0],y[n]=y[0],i=0;i<n;i++)
        s+=(x[i]*y[i+1]-x[i+1]*y[i]);
    printf("%.5Lf",s/2);
}