fork download
  1. #include <iostream>
  2. #include <cstring>
  3. using namespace std;
  4.  
  5. bool sieve[1000001];
  6.  
  7. int main() {
  8. memset(sieve, true, sizeof(sieve));
  9. sieve[1] = false;
  10. for(int i = 2; i*i <= 1000001; i++)
  11. if(sieve[i])
  12. for(int j = 2*i; j <= 1000001; j+=i)
  13. sieve[j] = false;
  14. int T;
  15. cin >> T;
  16. while(T--){
  17. int N, count = 0;
  18. cin >> N;
  19. for(int i = 1; i <= N; i++)
  20. if(sieve[i])
  21. count++;
  22. cout << count << endl;
  23. }
  24.  
  25. return 0;
  26. }
Success #stdin #stdout 0.01s 5284KB
stdin
2
9
11
stdout
4
5