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  1. #include <stdio.h>
  2. #include <math.h>
  3. #include <vector>
  4.  
  5. using namespace std;
  6.  
  7. int N,cnt = 0;
  8. vector<int> primes;
  9.  
  10. int is_prime(int p)
  11. {
  12.     int sq = sqrt(p);
  13.     for (int ps : primes) {
  14.         if(sq < ps)
  15.             return 1;
  16.         if(p % ps == 0)
  17.             return 0;
  18.     }
  19.     return 1;
  20. }
  21.  
  22. void prime(int N)
  23. {
  24.     int k = 0;
  25.     cnt += 2;
  26.     primes.push_back(2);
  27.     primes.push_back(3);
  28.     while (cnt < N) {
  29.         k++;
  30.         if(is_prime(6*k-1) == 1){
  31.             cnt ++;
  32.             primes.push_back(6*k-1);
  33.         }
  34.         if(is_prime(6*k+1) == 1){
  35.             cnt ++;
  36.             primes.push_back(6*k+1);
  37.         }
  38.     }
  39.     return;
  40. }
  41.  
  42. int main() {
  43.     int a;
  44.     scanf("%d",&a);
  45.     scanf("%d", &N);
  46.     prime(N);
  47.     if(a == 1) printf("%d",primes[N-1]);
  48.     if(a == 0) for(int x : primes)
  49.         printf("%d ",x);
  50.     return 0;
  51. }
Success #stdin #stdout 1.66s 8636KB
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https://ideone.com/0leEdu
language:
C++14 (gcc 8.3)
created:
10 days ago
visibility:
public

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