Cod sursa(job #983734)
Utilizator | adrian dumitrache addy01 | Data | 12 august 2013 16:49:40 |
---|---|---|---|
Problema | Aria | Scor | 0 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.49 kb |
#include <iostream>
#include <cstdio>
using namespace std;
struct punct
{
int x,y;
}v[100005];
double sol;
int main()
{
freopen("aria.in","r",stdin);
freopen("aria.out","w",stdout);
int n,i;
cin>>n;
for(i=1;i<=n;i++)
cin>>v[i].x>>v[i].y;
v[n+1].x=v[1].x;
v[n+1].y=v[1].y;
for(i=1;i<=n;i++)
sol+=(v[i].x*v[i+1].y-v[i].y*v[i+1].x);
if(sol<0)
cout<<sol*(-1)/2;
else
cout<<sol/2;
return 0;
}