Cod sursa(job #1054840)
Utilizator | Pintilie pintilie.andrei | Data | 14 decembrie 2013 10:23:19 |
---|---|---|---|
Problema | Aria | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.57 kb |
#include <cstdio>
#define NMAX 100010
using namespace std;
FILE *fin,*fout;
int n;
double a[NMAX],b[NMAX],S;
int main()
{
int i;
fin=fopen("aria.in","r");
fout=fopen("aria.out","w");
fscanf(fin,"%d",&n);
for(i=1;i<=n;i++)
fscanf(fin,"%lf%lf",&a[i],&b[i]);
for(i=1;i<=n;i++)
{
if(i!=n)
{
S=S+(a[i]*b[i+1]-a[i+1]*b[i]); //sa nu uit la afisare sa pun /2
}
else
{
S=S+(a[n]*b[1]-a[1]*b[n]);
}
}
fprintf(fout,"%lf",S/2);
return 0;
}