选数

#include<iostream>
#include<stdio.h>
#include<cmath>
#include<algorithm>
using namespace std;
int daan = 0;
int n, k;
int a[25] = { 0 };
bool paduan(int aa)
{
if (aa==0||aa==1)
{
return false;
}else{
for (int i = 2; i <=sqrt(aa); i++)
{
if (aa%i==0)
{
return false;
}
}
return true;
}
}
void dfs(int weizhi,int sum,int cishu)
{
if (cishu==k)
{
if (paduan(sum))
{
//          cout << sum << endl;
daan++;
}
}
else
{
if (weizhi<n&&cishu<k)
{
for (int i = weizhi+1; i <= n; i++)
{
dfs(i,sum+a[i],cishu+1);
}
}
}
}
int main()
{
cin >> n >> k;
for (int i = 1; i < n+1; i++)
{
cin >> a[i];
}
dfs(0,0,0);
cout << daan << endl;
system("pause");
return 0;
}