problem_2.py

"""
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.
"""

import time

#Attempt 1

start_time = time.time()

x, y = 1, 2
total = 0

while x < 4000000:
    x, y = y, x + y
    if not x & 1:
        total = total + x

print total

print time.time() - start_time, "seconds\n"

#Improvement 1

start_time = time.time()

x, y = 1, 2
total = 0

while x < 4000000:
    x, y = y, x + y
    if x % 2 == 0:
        total = total + x

print total

print time.time() - start_time, "seconds\n"