
Prime
By: a guest on
Oct 30th, 2010 | syntax:
Java | size: 0.52 KB | hits: 166 | expires: Never
public class BitSetPrime {
public static void main(String[] args) {
BitSet p=new BitSet(2000000);
p.flip(2,2000000); //Considering all numbers to be prime except 0 and 1
for(int i=2 ;i<2000000;i++)
{
if(!p.get(i))
continue;
else
// Set all multiples as not prime
for(int j = 2*i; j < 2000000; j += i)
p.set(j,false);
}
long sum=0;
for(int i = 2; i < 2000000; ++i)
if( p.get(i) ) // Add all nos with bit set
sum += i;
System.out.println(sum);
}
}