找规律得出答案就是比这个数大的最小素数
#include <iostream>
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <algorithm>
using namespace std;
#define LL long long
#define MAXN 1000010
int prim[MAXN];
LL a[MAXN];
bool num[MAXN];
void pre()
{
memset(num, 0, sizeof(num));
int k = 0;
for( int i = 2; i <= MAXN; i++)
{
if(!num[i])
{
prim[k++] = i;
for( int j = i; j <= MAXN; j += i)
num[j] = 1;
}
}
k = 0;
for( int i = 1; i <= MAXN; i++)
{
while(i >= prim[k])
k++;
a[i] = prim[k];
}
}
int main()
{
pre();
int n, m;
int val;
scanf("%d",&n);
int ca = 1;
while(n--)
{
scanf("%d",&m);
LL ans = 0 ;
for( int i = 0; i < m; i++)
{
scanf("%d",&val);
ans += a[val];
}
printf("Case %d: %lld Xukha\n",ca++,ans);
}
return 0;
}