https://www.codechef.com/COOK126C/problems/PTUPLES

help
1

#include <bits/stdc++.h>
#define ll long long int
#define ull unsigned long long int
#define INF 199999999600000001
#define MOD 1000000007
#define endl “\n”

using namespace std;

int good_prime(ll n)
{
vectorv(n,0);

// memset(v,0,sizeof(v));

ll p=2;
while(p*p<=n)
{    
    //marking the even no
    for(ll i=2;i*p<=n;++i) {
        v[i*p]=1;
    }
    //updating p
    for(ll i=p+1;i<=n;++i)
    {
        if(v[i]==0)
        {
            p=i;
            break;
        }
    }
}
// for(int i=2;i<=n;++i){
//     if(v[i]==0){
//         cout<<i<<" ";
//     }
// }
 int ans=0;
    //finding no of good prime no
    for(ll i=3;i+2<n;++i)
    {
        if(v[i]==0)
        {
            if(v[i+2]==0)ans++;
        }
    }

return ans;
}

int main()
{
ios_base::sync_with_stdio(false);
cin.tie(NULL);
ll t;
cin>>t;
while(t–)
{
ll n;cin>>n;
cout<<good_prime(n);

    cout<<endl;
}



return 0;

}