Cod sursa(job #3219248)
Utilizator | Anghel Laura Laura139 | Data | 30 martie 2024 16:20:01 |
---|---|---|---|
Problema | Aria | Scor | 0 |
Compilator | cpp-64 | Status | done |
Runda | Arhiva educationala | Marime | 0.52 kb |
#include <fstream>
using namespace std;
ifstream cin("aria.in");
ofstream cout("aria.out");
struct punct
{
int x,y;
}v[100005];
int main()
{
long long n,S=0,s;
cin>>n;
for(int i=1;i<=n;i++)
cin>>v[i].x>>v[i].y;
for(int i=1;i<=n;i++)
{
int j=i+1;
s=v[i].x*v[j].y-v[j].x*v[i].y;
S+=s;
}
s=v[n].x*v[1].y-v[1].x*v[n].y;
S+=s;
cout<<S/2;
if(S%2==1)
cout<<".5"<<'\n';
else
cout<<'\n';
return 0;
}