Returns the prime number and Euler's prime number by linear sieve (Euler's sieve ).

Returns the prime number and Euler's prime number by linear sieve (Euler's sieve ).

Time complexity O (n) WHEN n is large, the time used by the Euler's screening method is more and more obvious than the time used by the O (nloglogn) algorithm.

Why?

In the Euler's screening method, each sum is accessed only and the value of f [] is modified once.

For (I = 2; I <= n; I ++) {if (f [I] = 0) {p [++ cnt] = I ;} for (j = 1; j <= cnt; j ++) {if (I * p [j]> n) break; f [I * p [j] = 1; if (I % p [j] = 0) break ;}}