Cod sursa(job #2588687)
Utilizator | Petrea Nicoleta nicoletaptr2002 | Data | 25 martie 2020 12:02:32 |
---|---|---|---|
Problema | Dezastru | Scor | 10 |
Compilator | cpp-64 | Status | done |
Runda | Arhiva de probleme | Marime | 0.53 kb |
#include <bits/stdc++.h>
using namespace std;
int main () {
ifstream cin("dezastru.in");
ofstream cout("dezastru.out");
int N,k,x=0;
vector<int> v;
vector<double> s;
double a[26],aux,pr;
cin >> N >>k;
for(int i=0;i<N; ++i) cin>>a[i];
for (int i = 1; i <= N; ++i)
v.push_back(i);
do {
aux=1;
x++;
for(int i = 0; i<k; ++i) aux*=a[v[i]-1];
s.push_back(aux);
} while (next_permutation(v.begin(), v.end()));
for(int i=0; i<s.size(); i++) pr+= s[i]/x;
cout<<fixed<<setprecision(6)<<pr;
}