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48960268a2
* Improve Project Euler Problem 10 Sol-1 * Name correction * psf/black formatting * More formatting
57 lines
1.0 KiB
Python
57 lines
1.0 KiB
Python
"""
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Project Euler Problem 10: https://projecteuler.net/problem=10
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Summation of primes
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The sum of the primes below 10 is 2 + 3 + 5 + 7 = 17.
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Find the sum of all the primes below two million.
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References:
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- https://en.wikipedia.org/wiki/Prime_number
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"""
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from math import sqrt
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def is_prime(n: int) -> bool:
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"""
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Returns boolean representing primality of given number num.
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>>> is_prime(2)
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True
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>>> is_prime(3)
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True
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>>> is_prime(27)
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False
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>>> is_prime(2999)
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True
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"""
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if 1 < n < 4:
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return True
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elif n < 2 or not n % 2:
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return False
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return not any(not n % i for i in range(3, int(sqrt(n) + 1), 2))
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def solution(n: int = 2000000) -> int:
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"""
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Returns the sum of all the primes below n.
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>>> solution(1000)
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76127
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>>> solution(5000)
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1548136
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>>> solution(10000)
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5736396
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>>> solution(7)
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10
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"""
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return sum(num for num in range(3, n, 2) if is_prime(num)) + 2 if n > 2 else 0
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if __name__ == "__main__":
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print(f"{solution() = }")
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