第K极值

直接模拟

#include <cstdio>#include <algorithm>using namespace std;int a[10000];bool prime(int x){    if (x < 2)        return false;    for (int i = 2; i <= sqrt(x); i++)        if (x % i == 0)            return false;    return true;}int main(){    int n, k;    scanf("%d %d", &n, &k);    for (int i = 0; i < n; i++)        scanf("%d", &a[i]);    sort(a, a + n);    int ans = a[n - k] - a[k - 1];    if (prime(abs(ans))) printf("YES\n");    else printf("NO\n");    printf("%d\n", ans);    return 0;}

->原题地址<-