Almost Prime Numbers UVA - 10539

 

 

#include <iostream>
#include <cstring>
#include <cmath>
#include <algorithm>
using namespace std ; 

 const int M =1e6+33;
 #define int long long
 int b[M],c[M],tot;
 int s[M] ;
 
 void init(int top){
     memset(b,1,sizeof b); b[1]=0;
     int i,j;
     for(i=2;i<=top;i++){
         if(b[i]) c[++tot]=i;
         
        for(j=1;j<=tot&&i*c[j]<=top;j++){
             b[i*c[j]]=0;
             if(i%c[j]==0) break;
        } 
     }
 }
 
 signed main(){
 	init(1e6); 
 	int x,y,tes ;
 	cin>>tes;
 	while(tes--){
 		int ans =0;
 		cin>>x>>y; 
 		
 		for(int i=1;i<=tot;i++)
 			for(int j=c[i]*c[i];j<=y;j*=c[i])
 				if(j>=x) ans++;
 		cout<<ans<<'\n'; 
 	}
 }