mirror of
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e74adc4a6d
Rename the main solution functions to solution. Rename prime chec functions to is_prime. Add default args, typehints, expand variable names.
58 lines
1.2 KiB
Python
58 lines
1.2 KiB
Python
"""
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https://projecteuler.net/problem=10
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Problem Statement:
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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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"""
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import math
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from itertools import takewhile
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from typing import Iterator
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def is_prime(number: int) -> bool:
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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 number % 2 == 0 and number > 2:
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return False
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return all(number % i for i in range(3, int(math.sqrt(number)) + 1, 2))
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def prime_generator() -> Iterator[int]:
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num = 2
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while True:
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if is_prime(num):
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yield num
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num += 1
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def solution(n: int = 2000000) -> int:
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"""Returns the sum of all the primes below n.
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# The code below has been commented due to slow execution affecting Travis.
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# >>> solution(2000000)
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# 142913828922
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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(takewhile(lambda x: x < n, prime_generator()))
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if __name__ == "__main__":
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print(solution(int(input().strip())))
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