Cod sursa(job #1916191)
Utilizator | Gheorghe Stefan stefan_gheorghe | Data | 9 martie 2017 08:19:22 |
---|---|---|---|
Problema | Dezastru | Scor | 0 |
Compilator | cpp | Status | done |
Runda | Arhiva de probleme | Marime | 0.59 kb |
#include <fstream>
#include <iomanip>
using namespace std;
ifstream f("dezastru.in");
ofstream g("dezastru.out");
int n,m,sol[26];
float a[26],p,p1,s=0;
void load()
{
f>>n>>m;
for (int i=1; i<=n; i++) f>>a[i];
p=1;
for (int i=2; i<=n; i++) p*=i;
}
void dload()
{ p1=1;
for(int i=1;i<=m;i++) p1*=a[sol[i]];
s+=p1/p;
}
void back(int k)
{
if (k>m) dload();
else for (int i=sol[k-1]+1; i<=n; i++)
{
sol[k]=i;
back(k+1);
}
}
int main()
{
load(),back(1),g<<setprecision(6)<<fixed<<2*s;
return 0;
}