1 solutions

  • 0
    @ 2023-3-5 14:00:57
    #include <iostream>
    #include <cstdio>
    using namespace std;
    bool isprime(int a){
        if(a==1)return false;
        for(int i = 2; i * i <= a; i++)
            if(a % i == 0)
                return false;
        return true;
    }
    
    int n,k;
    int a[2005];
    long long ans;
    
    void dfs(int m, int sum, int startx){
        if(m == k){
            if(isprime(sum))
                ans++;
            return ;
        }
        for(int i = startx; i < n; i++)
            dfs(m + 1, sum + a[i], i + 1);
        return ;
    }
    
    int main(){
        scanf("%d%d",&n,&k);
        for(int i = 0; i < n; i++)
            scanf("%d",&a[i]);
        dfs(0, 0, 0);
        printf("%lld\n",ans);
        return 0;
    }
    
    • 1

    Information

    ID
    6701
    Time
    1000ms
    Memory
    256MiB
    Difficulty
    8
    Tags
    (None)
    # Submissions
    92
    Accepted
    14
    Uploaded By