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Segmented sieve - doctests #9945

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Oct 7, 2023
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28 changes: 26 additions & 2 deletions maths/segmented_sieve.py
Original file line number Diff line number Diff line change
Expand Up @@ -4,7 +4,26 @@


def sieve(n: int) -> list[int]:
"""Segmented Sieve."""
"""
Segmented Sieve.

Examples:
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Please add a doctest where the input itself is a prime number. For example,

>>> sieve(29)
[2, 3, 5, 7, 11, 13, 17, 19, 23, 29]

This is to clarify whether the algorithm includes the input number itself or not.

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In addition, please make sure that the function can correctly handle negative and zero inputs

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@tianyizheng02 corrected.

>>> sieve(8)
[2, 3, 5, 7]

>>> sieve(27)
[2, 3, 5, 7, 11, 13, 17, 19, 23]

"""

if n < 0:
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I would be OK to combine these into a single most be a positive integer.

What happens on floating point input?

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@quant12345 quant12345 Oct 6, 2023

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@cclauss

print(f"{sieve(87.5) = }")

Output

temp = [True] * (high - low + 1)
TypeError: can't multiply sequence by non-int of type 'float'

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Nice doctest to add.

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@cclauss question is off topic. For some reason, my old commits end up in pull requests. I don’t understand why this is so? Every time I make a new branch and they still get there.

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I will look in a few hours…

word = f"Number should not be negative n {n}"
raise ValueError(word)

if n == 0:
word = f"Number should not be zero n {n}"
raise ValueError(word)

in_prime = []
start = 2
end = int(math.sqrt(n)) # Size of every segment
Expand Down Expand Up @@ -42,4 +61,9 @@ def sieve(n: int) -> list[int]:
return prime


print(sieve(10**6))
if __name__ == "__main__":
import doctest

doctest.testmod()

print(sieve(10**6))
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Suggested change
print(sieve(10**6))
print(f"{sieve(10**6) = }")