Return all prime numbers smaller than M

Question

Given an integer M. return all prime numbers smaller than M.

Give a algorithm as good as you can. Need to consider time and space complexity.

Answer 1

The Sieve of Atkin is also the best algorithm to implement in this case and it takes only O(N) operations and O(N) space. Please refer https://en.wikipedia.org/wiki/Sieve_of_Atkin for detailed explanation of the algorithm and pseudocode.