Prime Generator - SPOJ Problem (Segmented Sieve)

#include<bits/stdc++.h>
#define endl "\n"
#define sp " "
#define ll long long
using namespace std;

const int MAX = 1000000;
bool sieve[MAX + 5];

void createSieve() {
    for(int i=2; i*i<=MAX; i++) {
        if(sieve[i] == 0) {
            for(int j=i*i; j<=MAX; j+=i) {
                sieve[j] = 1;
            }
        }
    }
}

vector<int> generatePrime(int n) {
    vector<int> primes;
    for(int i=2; i<=n; i++) {
        if(sieve[i]==0) primes.push_back(i);
    }
    return primes;
}

int main() {
    createSieve();
    int t, L, R;
    cin >> t;

    while(t--) {
        cin >> L >> R;
        int dummy[R-L+1];
        memset(dummy, 0, sizeof(dummy));
        if(L==1) dummy[0] = 1;
        vector<int> primes = generatePrime(sqrt(R));

        for(auto pr: primes) {
            int firstMultiple = (L/pr) * pr;
            if(firstMultiple < L) firstMultiple += pr;

            for(int i=max(firstMultiple, pr*pr); i<=R; i+=pr) {
                dummy[i-L] = 1;
            }
        }
        for(int i=L; i<=R; i++) {
            if(dummy[i-L]==0) cout << i << endl;
        }
        cout << endl;
    }


    return 0;
}