Project Euler - 2

피보나치 수

4백만 미만의 피보나치 수 중에서 짝수인 것들의 합을 구하라.

"""
Even Fibonacci numbers

Each new term in the Fibonacci sequence is generated by adding the previous two terms.
By starting with 1 and 2, the first 10 terms will be:

1, 2, 3, 5, 8, 13, 21, 34, 55, 89, ...

By considering the terms in the Fibonacci sequence whose values do not exceed four million,
find the sum of the even-valued terms.
"""


class Fibonacci:
    def __init__(self):
        self.a = 0
        self.b = 1

    def __iter__(self):
        return self

    def __next__(self):
        c = self.a + self.b
        if self.a > self.b:
            self.b = c
        else:
            self.a = c
        return c


if __name__ == '__main__':
    s = 0
    fibonacci = Fibonacci()
    for n in fibonacci:
        if n >= 4000000:
            break
        else:
            if n % 2 == 0:
                s += n
    print(s)

https://projecteuler.net/problem=2

피보나치 수열을 구하기 위해서 Iterator 클래스를 구현하였다.