### Prime Generator

Below given code is for prime1 spoj or prime generator spoj .

This code will run for PRINT - prime intervals also .

#include <bits/stdc++.h> using namespace std; vector<int > prime; bool check[50009]; int keep = 1; void pre() { check[1 ] = 1; for(int i = 3 ; i <=224 ; i+=2){ if(!check[i]){ for(int j = i*i ; j<= 50000 ; j+=2*i) check[j] = true; } } prime.push_back(2); keep=1; for(int i = 3 ; i<= 50000 ; i++) if(check[i] == false && (i&1)) prime.push_back(i) , keep++; } bool seg[1000009]; int main() { int t; scanf("%d",&t); pre(); while(t--) { int a , b; scanf("%d%d",&a , &b); if(b <= 50000){ if(a<=2) printf("2\n"); for(int i = a ; i<= b ; i++){ if(check[i] == false && (i&1)) printf("%d\n", i); } continue; } memset(seg , 0 , sizeof seg); for(int i = 0; prime[i]*prime[i] <= b ; i++) { int begin = a/prime[i]; begin *= prime[i]; for(int j = begin ; j<= b ; j+= prime[i]){ if(j < a) continue; seg[j - a] = true; } } for(int i = 0 ; prime[i]*prime[i] <= b ; i++){ if(prime[i]>= a && prime[i]<=b) printf("%d\n",prime[i]); } for(int i = a==1?1:0 ; i < b-a+1 ; i++) if(seg[i]==0) printf("%d\n", i+a); } return 0; }