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| -rw-r--r-- | challenge-172/walt-mankowski/python/primes.py | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/challenge-172/walt-mankowski/python/primes.py b/challenge-172/walt-mankowski/python/primes.py new file mode 100644 index 0000000000..686143de0f --- /dev/null +++ b/challenge-172/walt-mankowski/python/primes.py @@ -0,0 +1,15 @@ +from math import sqrt + +# find the primes up to n using the sieve of Eratosthenes and return +# them as list +def primes_to(n): + is_prime = [True] * (n+1) + is_prime[0] = is_prime[1] = False + for i in range(2, int(sqrt(n))+1): + if is_prime[i]: + for j in range(i+i, n+1, i): + is_prime[j] = False + + return [i for i,val in enumerate(is_prime) if val] + + |