Uva 10533 - Digit Primes

 

// Verdict:: Accepted
// Time:: 0.145
#include <iostream>
#include <cstdio>
#include <cstring>
#include <map>
#include <string>
#include <vector>
#include <cmath>
#include <cctype>
#include <sstream>
#include <set>
#include <list>
#include <stack>
#include <queue>
#include <algorithm>
#define sf scanf
#define pf printf
#define sfint scanf ("%d %d",&a,&b)
#define sfl scanf ("%ld %ld",&a,&b)
#define sfll scanf ("%lld %lld",&a,&b)
#define sfd scanf ("%lf %lf",&a,&b)
#define sff scanf ("%f %f",&a,&b)
#define lp1(i,n) for(i=0;i<n;i++)
#define lp2(i,n) for(i=1;i<=n;i++)
#define LL long long
#define L long
#define mem(c,v) memset(c,v,sizeof(c))
#define ui unsigned int
#define ull unsigned long long int
#define nl puts("")
#define MX 1000005
#define N 100
#define MOD 10000000007
#define pb push_back
#define pi acos(-1.0)
#define sz size()
#define gc getchar ()
#define ps push
#define clr clear
#define bn begin()
#define ed end()

using namespace std;

LL prime[MX],digit[MX],len=0;

LL dig_sum(LL n)
{
    LL s=0;
    while(n>0)
    {
        s+=(n%10);
        n/=10;
    }

    return s;
}

LL setbit(LL n, LL pos)
{
    n=n|(1<<pos);
    return n;
}

bool checkbit(LL n, LL pos)
{
    n=n&(1<<pos);
    return n;
}

// generating bitwise seieve
void seieve(LL n)
{
    LL x=sqrt(n);
    prime[0]=setbit(prime[0],0);
    prime[0]=setbit(prime[0],1);

    LL i,j,cnt=0;

    for(i=4;i<=n;i+=2) prime[i>>5]=setbit(prime[i>>5],i&31);

    for(i=3;i<=x;i+=2)
    {
        if(!checkbit(prime[i>>5],i&31))
        {
            for(j=i*i;j<=n;j+=i)
            {
                prime[j>>5]=setbit(prime[j>>5],j&31);
            }
        }
    }

    for(i=0;i<=n;i++)
    {
        if(!checkbit(prime[i>>5],i&31))
        {
            LL r = dig_sum(i);

            if((!checkbit(prime[r>>5],r&31)))
            {
                cnt+=1;
            }
        }

        digit[len++]=cnt; // store the total number of prime till n with one by one(i)
    }
}

int main()
{
    seieve(MX);
    L t; sf("%ld",&t);

    while(t--)
    {
        LL x,y;
        sf("%lld %lld",&x,&y);
        pf("%lld\n",digit[y]-digit[x-1]);
    }

    return 0;
}