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98e9d6bdb6
* Fix style of the first ten solutions for Project Euler - Unify the header docstring, and add reference URLs to wikipedia or similar - Fix docstrings to be properly multilined - Add newlines where appropriate - Add doctests where they were missing - Remove doctests that test for the correct solution - fix obvious spelling or grammar mistakes in comments and exception messages - Fix line endings to be UNIX. This makes two of the files seem to have changed completely - no functional changes in any of the solutions were done (except for the spelling fixes mentioned above) * Fix docstrings and main function as per Style Guide
77 lines
1.3 KiB
Python
77 lines
1.3 KiB
Python
"""
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Project Euler Problem 7: https://projecteuler.net/problem=7
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10001st prime
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By listing the first six prime numbers: 2, 3, 5, 7, 11, and 13, we
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can see that the 6th prime is 13.
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What is the 10001st prime number?
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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(num: int) -> bool:
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"""
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Determines whether the given number is prime or not
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>>> is_prime(2)
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True
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>>> is_prime(15)
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False
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>>> is_prime(29)
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True
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>>> is_prime(0)
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False
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"""
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if num == 2:
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return True
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elif num % 2 == 0:
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return False
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else:
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sq = int(sqrt(num)) + 1
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for i in range(3, sq, 2):
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if num % i == 0:
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return False
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return True
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def solution(nth: int = 10001) -> int:
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"""
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Returns the n-th prime number.
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>>> solution(6)
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13
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>>> solution(1)
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2
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>>> solution(3)
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5
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>>> solution(20)
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71
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>>> solution(50)
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229
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>>> solution(100)
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541
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"""
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count = 0
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number = 1
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while count != nth and number < 3:
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number += 1
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if is_prime(number):
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count += 1
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while count != nth:
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number += 2
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if is_prime(number):
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count += 1
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return number
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if __name__ == "__main__":
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print(f"{solution() = }")
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