questions on a particular algorithm
- by paul smith
Upon searching for a fast primr algorithm, I stumbled upon this:
public static boolean isP(long n) {
if (n==2 || n==3) return true;
if ((n&0x1)==0 || n%3==0 || n<2) return false;
long root=(long)Math.sqrt(n)+1L;
// we check just numbers of the form 6*k+1 and 6*k-1
for (long k=6;k<=root;k+=6) {
if…
