TDPRIMES SPOJ SOLUTION

/* PRINTING SOME PRIMES SPOJ SOLUTION*/

#include<bits/stdc++.h>
using namespace std;
vector <bool> v(100000000,true);
int arr[8000000];
int main()
{
    long long int n = 100000000;
    long int i,j ;
    v[1] = false;
    v[0] = false;
    for(i=4;i<=n;i+=2)
     v[i]=false;
      for(i=3;i*i<=n;i+=2)
     {
           if(v[i])
             {
                for(j=i*i;j<=n;j=j+(2*i))
                v[j] = false;
             }
     }
       j=0;
       arr[0] = 2;
       for(i=3;i<=n;i+=2)
      {
        if(v[i])
        arr[++j]=i;
       }
       for(i=1;i<=j;i+=100)
      cout<<arr[i-1]<<"\n";
      return 0;
   }

Comments

  1. why to check if(v[i]==true) in the nested for
    since we are checking for odd numbers it will already be true.

    ReplyDelete
    Replies
    1. if(v[i]==true) in nested for , by this we are checking that if ' i ' is prime or not

      Delete

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