Cod sursa(job #2285843)
Utilizator | Isac Lucian IsacLucian | Data | 19 noiembrie 2018 13:22:39 |
---|---|---|---|
Problema | Aria | Scor | 70 |
Compilator | cpp-64 | Status | done |
Runda | Arhiva educationala | Marime | 0.5 kb |
#include <bits/stdc++.h>
using namespace std;
ifstream fin("aria.in");
ofstream fout("aria.out");
int n;
struct Puncte
{
double x,y;
}a[100005];
int main()
{
fin>>n;
for(int i=1;i<=n;i++)
fin>>a[i].x>>a[i].y;
double sol=0;
a[n+1].x=a[1].x;
a[n+1].y=a[1].y;
for(int i=1;i<=n;i++)
sol+=(a[i].x*a[i+1].y-a[i].y*a[i+1].x);
fout<<fixed<<setprecision(6)<<fabs(sol/2.0)<<"\n";
fin.close();
fout.close();
return 0;
}