[C++] 17014 - Pretty Average Primes

문제 링크 : https://www.acmicpc.net/problem/17014

17014번: Pretty Average Primes

 

 

 

 

 

#include<iostream>
#include<algorithm>
#define endl '\n'
 
using namespace std;
 
bool eratos[2000005];
 
void E()
{
    for(int i = 2; i*2 <= 2000005; ++i)
    {
        if(!eratos[i])
        {
            for(int j = i*2; j <= 2000005; j += i)
                eratos[j] = 1;
        }
    }
}
 
int main(void)
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
 
    E();
 
    int n;
    int T;
    cin >> n;
    while(n--)
    {
        cin >> T;
        for(int i = 0; i < T-1; ++i)
        {
            if(!eratos[T+i] && !eratos[T-i])
            {
                cout << T-i << ' ' << T+i << endl;
                break;
            }
        }
    }
 
    return 0;
}