Cod sursa(job #2348041)
Utilizator | Marin Vasile Peptenaru MarinPeptenaru | Data | 19 februarie 2019 12:17:27 |
---|---|---|---|
Problema | Aria | Scor | 70 |
Compilator | cpp-64 | Status | done |
Runda | Arhiva educationala | Marime | 0.49 kb |
#include <bits/stdc++.h>
using namespace std;
ifstream in("aria.in");
ofstream out("aria.out");
struct punct
{
double x;
double y;
};
double arie_tri (punct a, punct b)
{
return a.x*b.y-b.x*a.y;
}
double sol;
int n;
punct v[100001];
int main()
{
in>>n;
for(int i=1; i<=n; i++)
in>>v[i].x>>v[i].y;
for(int i=1; i<n; i++)
sol+=arie_tri(v[i],v[i+1]);
sol+=(arie_tri(v[n],v[1]));
sol/=2;
out<<fixed<<sol;
return 0;
}