Project Euler - 3

최대 소인수

600851475143의 소인수 중에서 최대 값을 구하라.

"""
Largest prime factor

The prime factors of 13195 are 5, 7, 13 and 29.

What is the largest prime factor of the number 600851475143 ?
"""


class PrimeNumber:
    def __init__(self):
        self.current = 1
        self.num_set = set()

    def __iter__(self):
        return self

    def __next__(self):
        self.current += 1
        while True:
            for i in self.num_set:
                if self.current % i == 0:
                    self.current += 1
                    break  # Break current for loop
            else:
                break  # Break the while loop and return
        self.num_set.add(self.current)
        return self.current


if __name__ == '__main__':
    number = 600851475143
    prime_number = PrimeNumber()
    for n in prime_number:
        if n > number:
            break
        if number % n == 0:
            print(n)

https://projecteuler.net/problem=3

소수를 구하기 위해 Iterator를 구현하였다.