Project Euler 2

• 問題

Problem 2：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.

• 解答例

kf1 = 1
kf2 = 2
sum = 2

while (kf1 + kf2) < 4000000:
    kf3 = kf1 + kf2
    if kf3 % 2 == 0:
        sum += kf3
    kf1, kf2 = kf2, kf3

print(sum)