Cod sursa(job #2595208)
Utilizator | Data | 7 aprilie 2020 12:38:46 | |
---|---|---|---|
Problema | Aria | Scor | 0 |
Compilator | cpp-64 | Status | done |
Runda | Arhiva educationala | Marime | 0.49 kb |
#include <iostream>
#include <fstream>
using namespace std;
ifstream fin("aria.in");
ofstream fout("aria.out");
#define ll long long
struct punct
{
ll x,y;
}P[100005];
ll N,rez;
int main()
{
fin >> N;
ll i;
for (i=1;i<=N;++i)
{
fin >> P[i].x >> P[i].y;
}
P[N+1]=P[1];
for (i=1;i<=N;++i)
{
rez+=(P[i].x*P[i+1].y-P[i+1].x*P[i].y);
}
rez/=2;
fout << rez;
fin.close();
fout.close();
return 0;
}