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| 1 | +#author-slayking1965 |
| 2 | +""" |
| 3 | +https://projecteuler.net/problem=10 |
| 4 | +Problem Statement: |
| 5 | +The sum of the primes below 10 is 2 + 3 + 5 + 7 = 17. |
| 6 | +Find the sum of all the primes below two million using Sieve_of_Eratosthenes: |
| 7 | +The sieve of Eratosthenes is one of the most efficient ways to find all primes |
| 8 | +smaller than n when n is smaller than 10 million. Only for positive numbers. |
| 9 | +Find the sum of all the primes below two million. |
| 10 | +""" |
| 11 | + |
| 12 | + |
| 13 | +def prime_sum(n: int) -> int: |
| 14 | + """Returns the sum of all the primes below n. |
| 15 | +def solution(n: int = 2000000) -> int: |
| 16 | + """Returns the sum of all the primes below n using Sieve of Eratosthenes: |
| 17 | + https://en.wikipedia.org/wiki/Sieve_of_Eratosthenes |
| 18 | + The sieve of Eratosthenes is one of the most efficient ways to find all primes |
| 19 | + smaller than n when n is smaller than 10 million. Only for positive numbers. |
| 20 | + >>> prime_sum(2_000_000) |
| 21 | + >>> solution(2_000_000) |
| 22 | + 142913828922 |
| 23 | + >>> prime_sum(1_000) |
| 24 | + >>> solution(1_000) |
| 25 | + 76127 |
| 26 | + >>> prime_sum(5_000) |
| 27 | + >>> solution(5_000) |
| 28 | + 1548136 |
| 29 | + >>> prime_sum(10_000) |
| 30 | + >>> solution(10_000) |
| 31 | + 5736396 |
| 32 | + >>> prime_sum(7) |
| 33 | + >>> solution(7) |
| 34 | + 10 |
| 35 | + >>> prime_sum(7.1) # doctest: +ELLIPSIS |
| 36 | + >>> solution(7.1) # doctest: +ELLIPSIS |
| 37 | + Traceback (most recent call last): |
| 38 | + ... |
| 39 | + TypeError: 'float' object cannot be interpreted as an integer |
| 40 | + >>> prime_sum(-7) # doctest: +ELLIPSIS |
| 41 | + >>> solution(-7) # doctest: +ELLIPSIS |
| 42 | + Traceback (most recent call last): |
| 43 | + ... |
| 44 | + IndexError: list assignment index out of range |
| 45 | + >>> prime_sum("seven") # doctest: +ELLIPSIS |
| 46 | + >>> solution("seven") # doctest: +ELLIPSIS |
| 47 | + Traceback (most recent call last): |
| 48 | + ... |
| 49 | + TypeError: can only concatenate str (not "int") to str |
| 50 | + """ |
| 51 | + list_ = [0 for i in range(n + 1)] |
| 52 | + list_[0] = 1 |
| 53 | + list_[1] = 1 |
| 54 | + primality_list = [0 for i in range(n + 1)] |
| 55 | + primality_list[0] = 1 |
| 56 | + primality_list[1] = 1 |
| 57 | + |
| 58 | + for i in range(2, int(n ** 0.5) + 1): |
| 59 | + if list_[i] == 0: |
| 60 | + if primality_list[i] == 0: |
| 61 | + for j in range(i * i, n + 1, i): |
| 62 | + list_[j] = 1 |
| 63 | + s = 0 |
| 64 | + primality_list[j] = 1 |
| 65 | + sum_of_primes = 0 |
| 66 | + for i in range(n): |
| 67 | + if list_[i] == 0: |
| 68 | + s += i |
| 69 | + return s |
| 70 | + if primality_list[i] == 0: |
| 71 | + sum_of_primes += i |
| 72 | + return sum_of_primes |
| 73 | + |
| 74 | + |
| 75 | +if __name__ == "__main__": |
| 76 | + # import doctest |
| 77 | + # doctest.testmod() |
| 78 | + print(prime_sum(int(input().strip()))) |
| 79 | + print(solution(int(input().strip()))) |
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