Submission #1925686

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Source Code Expand

#include <bits/stdc++.h>

using namespace std;

inline bool IsPrime( int number )
{
 if ( ( (!(number & 1)) && number != 2 ) || (number < 2) || (number % 3 == 0 && number != 3) )
  return (false);

 for( int k = 1; 36*k*k-12*k < number;++k)
  if ( (number % (6*k+1) == 0) || (number % (6*k-1) == 0) )
   return (false);
  return true;
 }

int main()
{
    int n, i, j, a, b, c;
    cin>>n;
    for(i=0;i<n;i++){
        c=0;
        cin>>a>>b;
        for(j=a;j<=b;j++){
            if(IsPrime(j) && IsPrime((j+1)/2))
                c++;
        }
        cout<<c<<endl;
    }
    return 0;
}

Submission Info

Judge Result