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Change prime_sieve_eratosthenes.py to return list (#8062)

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Tianyi Zheng 2023-01-01 17:10:59 -08:00 committed by GitHub
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commit 7c1d23d448
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1 changed files with 22 additions and 13 deletions
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maths/prime_sieve_eratosthenes.py
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@ -1,10 +1,10 @@
""" """
Sieve of Eratosthenes Sieve of Eratosthenes
Input : n =10 Input: n = 10
Output: 2 3 5 7 Output: 2 3 5 7
Input : n = 20 Input: n = 20
Output: 2 3 5 7 11 13 17 19 Output: 2 3 5 7 11 13 17 19
you can read in detail about this at you can read in detail about this at
@ -12,34 +12,43 @@ https://en.wikipedia.org/wiki/Sieve_of_Eratosthenes
""" """
def prime_sieve_eratosthenes(num): def prime_sieve_eratosthenes(num: int) -> list[int]:
""" """
print the prime numbers up to n Print the prime numbers up to n
>>> prime_sieve_eratosthenes(10) >>> prime_sieve_eratosthenes(10)
2,3,5,7, [2, 3, 5, 7]
>>> prime_sieve_eratosthenes(20) >>> prime_sieve_eratosthenes(20)
2,3,5,7,11,13,17,19, [2, 3, 5, 7, 11, 13, 17, 19]
>>> prime_sieve_eratosthenes(2)
[2]
>>> prime_sieve_eratosthenes(1)
[]
>>> prime_sieve_eratosthenes(-1)
Traceback (most recent call last):
...
ValueError: Input must be a positive integer
""" """
primes = [True for i in range(num + 1)] if num <= 0:
p = 2 raise ValueError("Input must be a positive integer")
primes = [True] * (num + 1)
p = 2
while p * p <= num: while p * p <= num:
if primes[p]: if primes[p]:
for i in range(p * p, num + 1, p): for i in range(p * p, num + 1, p):
primes[i] = False primes[i] = False
p += 1 p += 1
for prime in range(2, num + 1): return [prime for prime in range(2, num + 1) if primes[prime]]
if primes[prime]:
print(prime, end=",")
if __name__ == "__main__": if __name__ == "__main__":
import doctest import doctest
doctest.testmod() doctest.testmod()
num = int(input())
prime_sieve_eratosthenes(num) user_num = int(input("Enter a positive integer: ").strip())
print(prime_sieve_eratosthenes(user_num))