Cod sursa(job #2416806)
Utilizator | Data | 28 aprilie 2019 11:52:43 | |
---|---|---|---|
Problema | Dezastru | Scor | 60 |
Compilator | cpp-64 | Status | done |
Runda | Arhiva de probleme | Marime | 0.54 kb |
#include<fstream>
using namespace std;
ifstream cin("dezastru.in");
ofstream cout("dezastru.out");
int n,m;
double v[105];
double s,p=1;
double rez;
void comb(int k,int ant){
if(k==m+1){
s+=p;
return;
}
for(int i=ant+1;i<=n;i++){
p*=v[i];
comb(k+1,i);
p/=v[i];
}
}
int main(){
cin>>n>>m;
for(int i=1;i<=n;i++)
cin>>v[i];
comb(1,0);
for(int i=1;i<=m;i++){
s/=n-m+i;
s*=i;
}
cout<<s;
}