Interval sieve method

Interval sieve method

For \ ([2, \ sqrt { b}] \) simultaneously to the Eppendorf sieve interval \ ([a, b] \ ) screening

const int maxlen=1e6+5;
const int max_sqrt_b=1e7+5;
bool bj[max_sqrt_b],is_prime[maxlen];
void solve(ll a,ll b)
{
    fill(bj,bj+sizeof(bj),1);
    fill(is_prime,is_prime+sizeof(is_prime),1);
    for(ll i=2;i*i<=b;++i){
        if(bj[i]){
            for(ll j=2*i;j*j<=b;j+=i)
                bj[j]=0;
            for(ll j=max(2ll,(a+i-1)/i)*i;j<=b;j+=i)
                is_prime[j-a]=0;
        }
    }
}