P1001 （C语言代码）

解题思路:

注意事项:

参考代码:

#include<iostream>

#include<vector>

#include<algorithm>

using namespace std;

void is_prime(int n)

{

if (n<2)cout << "NO" << endl;

else if (n == 2)cout << "YES" << endl;

else

{

int ok = 1;

for (int i = 2; i*i<n; i++)

{

if (n%i == 0)

{

ok = 0;

break;

}

}

if (ok)cout << "YES" << endl;

else cout << "NO" << endl;

}

}

int main()

{

int n, k;

cin >> n >> k;

vector<int>a(n);

for (int i = 0; i<a.size(); i++)

cin >> a[i];

sort(a.begin(), a.end());

int m = a[n - k] - a[k - 1];

is_prime(m);

cout << m << endl;

return 0;

}