Cod sursa(job #1609217)
Utilizator | Data | 22 februarie 2016 17:52:30 | |
---|---|---|---|
Problema | Aria | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva educationala | Marime | 0.54 kb |
#include <bits/stdc++.h>
using namespace std;
ifstream in ("aria.in");
ofstream out ("aria.out");
struct punct
{
long double x,y;
};
int main()
{
long double a = 0, b = 0;
int n;
in>>n;
punct pct[n+10];
for(int i = 1; i <= n; i++)
in>>pct[i].x>>pct[i].y;
pct[n+1].x = pct[1].x;
pct[n+1].y = pct[1].y;
for(int i = 1; i <= n; i++)
{
a = a + pct[i].x * pct[i+1].y - pct[i+1].x * pct[i].y;;
}
out << fixed<<setprecision(6)<<a/(long double)2;
return 0;
}