euler/e002.py

"""Find the sum of all the even-valued terms in the Fibonacci sequence which do not exceed four million.

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, ...
Find the sum of all the even-valued terms in the sequence which do not exceed four million.
"""

def main():
    limit = 4000000
    #limit = 90
    last = [0, 1]
    x = 1
    total = 0
    while (x < limit):
        if (0 == x % 2):
            total += x
        last.append(x)
        last = last[-2:]
        x = sum(last)
    print 'Answer', total

if __name__ == '__main__':
    main()