Cod sursa(job #1472391)

Utilizator BlaugranasEnal Gemaledin Blaugranas Data 17 august 2015 03:34:26
Problema Aria Scor 70
Compilator c Status done
Runda Arhiva educationala Marime 0.34 kb
Raporteaza aceasta sursa 
#include<stdio.h>
#include<math.h>
int n,i;
double s,a[100000],b[100000];
int main() {
    freopen("aria.in","r",stdin),freopen("aria.out","w",stdout),scanf("%d",&n);
    for(i=0;i<n;i++)
        scanf("%lf%lf",a+i,b+i);
    for(a[n]=a[0],b[n]=b[0],i=0;i<n;i++)
        s+=(a[i]*b[i+1]-a[i+1]*b[i]);
    printf("%.5lf",fabs(s/2.0));
}